UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 


COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


TOLERANCE  OF  EUCALYPTUS  FOR  ALKALI 

WITH  PARTIAL  REPRINT  fROM  BULLETIN  196 

By  R.  H.  LOUGHRIDGE 


BULLETIN  No.  225 

(Berkeley,  Cal.,  October,  1911) 


SACRAMENTO 
Friend  Wm.  Richardson     -     -     -     Superintendent  of  State  Printing 

1911 


Benjamin  Ide  Wheeler,  President  of  the  University. 

EXPERIMENT    STATION    STAFF. 

E.  J.  Wickson,  M.A.,  Director  and  Horticulturist. 

E.  W.  Hilgard,  Ph.D.,  LL.D.,  Chemist  (Emeritus). 

W.  A.  Setchell,  Ph.D.,  Botanist. 

Leroy  Anderson,  Ph.D.,  Dairy  Industry  and  Superintendent  University  Farm  Schools. 

M.  E.  Jaffa,  M.S.,  Nutrition  Expert. 

R.   H.  Loughridge,  Ph.D.,   Soil  Chemist  and  Physicist    (Emeritus). 

C.  W.  Woodworth,  M.S.,  Entomologist. 

Ralph  E.   Smith,  B.S.,  Plant  Pathologist  and  Superintendent  of  Southern  California 

Pathological  Laboratory  and  Experiment  Station. 
G.  W.  Shaw,  M.A.,  Ph.D.,  Experimental  Agronomist  and  Agricultural  Technologist,  in 

charge  of  Cereal  Stations. 

E.  W.  Major,  B.Agr.,  Animal  Industry. 

B.  A.  Etcheverry,  B.S.,  Irrigation  Expert. 

F.  T.  Bioletti,  B.S.,  Viticulturist. 

W.  T.  Clarke,  B.S.,  Assistant  Horticulturist  and  Superintendent  of  University  Exten- 
sion in  Agriculture. 

John  S.  Burd,  B.S.,  Chemist,  in  charge  of  Fertilizer  Control. 

J.  E.  Coit,  Ph.D.,  Assistant  Pomologist,  Plant  Disease  Laboratory,  Whittier. 

George  E.  Colby,  M.S.,  Chemist  (Fruits,  Waters,  and  Insecticides),  in  charge  of 
Chemical  Laboratory. 

H.  J.  Quayle,  M.S.,  Assistant  Entomologist,  Plant  Disease  Laboratory,  Whittier. 

H.  M.  Hall,  Ph.D.,  Assistant  Botanist. 

C.  M.  Haring,  D.V.M.,  Assistant  Veterinarian  and  Bacteriologist. 
E.  B.  Babcock,  B.S.,  Assistant  Agricultural  Education. 

W.  B.  Herms,  M.A.,  Assistant  Entomologist. 

J.  H  Norton,  M.S.,  Assistant  Chemist,  in  charge  of  Citrus  Experiment  Station,  River- 
side. 
W.  T.  Horne,  B.S.,  Assistant  Plant  Pathologist. 
C.  B.  Lipman,  Ph.D.,  Soil  Chemist  and  Bacteriologist. 

Mansell,  Assistant  Horticulturist,  in  charge  of  Central  Station  grounds. 

Gaumnitz,  Assistant  Agronomist,  University  Farm,  Davis. 

Ingham,  B.S.,  Assistant  in  Sylviculture,  Santa  Monica. 

Hunt,  B.S.,  Assistant  Plant  Pathologist. 

McCreary,  B.S.,  Chemist  in  Fertilizer  Control. 

Hagemann,  Assistant  in  Dairying,  Davis. 

Roberts,  Farm  Manager,  University  Farm,  Davis. 

B.  S.  Brown,  B.S.A.,  Assistant  Horticulturist,  University  Farm,  Davis. 
J.  I.  Thompson,  B.S.,  Assistant  Animal  Industry,  Davis. 

Howard  Phillips,  B.S.,  Assistant  Animal  Industry,  Davis. 
J.  C.  Bridwell,  B.S.,  Assistant  Entomologist. 

C.  H.  McCharles,  M.S.,  Assistant  Agricultural  Chemical  Laboratory. 

E.  H.  Smith,  M.S.,  Assistant  Plant  Pathologist. 

C.  O.  Smith,  M.S.,  Assistant  Plant  Pathologist,  Plant  Disease  Laboratory,  Whittier. 

F.  E.  Johnson,  B.L.,  M.S.,  Assistant  Soil  Chemist. 

B.  A.  Madson,  B.S.A.,  Assistant  Experimental  Agronomist. 

Walter  E.  Packard,  M.S.,  Field  Assistant  Imperial  Valley  Investigation,  El  Centre 

P.  L.  Hibbard,  B.S.,  Assistant  Fertilizer  Control  Laboratory. 

L.  M.  Davis,  B.S.,  Assistant  in  Dairy  Husbandry,  University  Farm,  Davis. 

S.  S.  Rogers,  B.S.,  Assistant  Plant  Pathologist,  Plant  Disease  Laboratory,  Whittier. 

L.  Bonnet,  Assistant  Viticulturist. 

H.  A.  Ruehe,  B.S.A.,  Assistant  in  Dairy  Husbandry,  University  Farm,  Davis. 

F.  C.  H.  Flossfeder,  Assistant  in  Viticulture,  University  Farm,  Davis. 

S.  D.  Wilkins,  Assistant  in  Poultry  Husbandry,  University  Farm,  Davis. 

C.  L.  Roadhouse,  D.V.M.,  Assistant  in  Veterinary  Science. 
F.  M.  Hayes,  D.V.M.,  Assistant  Veterinarian. 

F.  L.  Yeaw,  B.S.,  Assistant  Plant  Pathologist,  University  Farm,  Davis. 
M.  E.  Stover,  B.S.,  Assistant  in  Agricultural  Chemical  Laboratory. 

W.  H.  Volck,  Field  Assistant  in  Entomology,  Watsonville. 

E.  L.  Morris,  Field  Assistant  in  Entomology,  San  Jose. 

E.  E.  Thomas,  B.S.,  Assistant  Chemist,  Plant  Disease  Laboratory,  Whittier. 

A.  B.  Shaw,  B.S.,  Assistant  in  Entomology. 

G.  P.  Gray,  M.S.,  Chemist  in  Insecticides. 

H.   D.   Young,   B.S.,   Assistant  in  Agricultural   Chemistry,   Plant  Disease   Laboratory, 

Whittier. 
A.  R.  Tylor,  B.S.,  Assistant  in  Plant  Pathology,  Plant  Disease  Laboratory,  Whittier. 
E.  W.  Rust,  A.B.,  Assistant  in  Entomology,  Plant  Disease  Laboratory,  Whittier. 
L.  T.  Sharp,  B.S.,  Assistant  in  Soils. 
W.  W.  Cruess,  B.S.,  Assistant  in  Zymology. 
J.  F.  Mitchell,  D.V.M.,  Assistant  in  Veterinary  Laboratory. 
W.  B.  Boys,  Assistant  Cerealist. 

Anna  M.  Lute,  Scientific  Assistant,  United  States  Department  of  Agriculture. 
J.  C.  Roper,  Patron,  University  Forestry  Station,  Chico. 
E.  C.  Miller,  Foreman,  Forestry  Station,  Chico. 

D.  L.  Bunnell,  Secretary  to  Director. 


R. 

E. 

A. 

J. 

N. 

D. 

T. 

F. 

P. 

L. 

E. 

II. 

R. 

M. 

TABLE  OF  CONTENTS. 


Page. 
INTRODUCTION    __ 247 

CONDITIONS  TO  BE  MET  IN  THE  INVESTIGATION 248 

Differences  in  action  of  alkali  salts 249 

Irregular  distribution  of  alkali  salts 250 

Alkali  exists  in  limited  instead  of  on  large  areas 251 

Movement  of  alkali  in  the  soil 251 

Development  of  eucalyptus  root  system 252 

DESCRIPTION  OF  THE  SEEDLING  TEST  PLOT,  TULARE  STATION__  254 

Distribution  of  alkali  in  the  test  plot:    with  chart 254 

Condition  of  seedlings  at  end  of  season  :  with  chart 258 

EFFECT  OF  ALKALI  UPON  VARIOUS  SPECIES  OF  EUCALYPTS 259 

Eucalyptus  corynocalyx  in  Tulare  test  plot,  Hanford  and  Fresno__  260 

Eucalyptus  crebra  in  Tulare  test  plot 261 

Eucalyptus  cornuta  in  Tulare  test  plot 263 

Eucalyptus  globulus  in  Tulare  test  plot,  Buena  Park  and  Fresno  ; 

also  in  salt  marshes 264 

Eucalyptus  rudis  in  Tulare  test  plot,  Fresno,  Hanford  and  Kings- 
burg  272 

Eucalyptus  tereticornis  in  Tulare  test  plot 276 

Eucalyptus  rostrata  in  Tulare  test  plot,  Buena  Park  and  Mira- 

MONTE     277 

Eucalyptus  botryoides  near  Kingsburg,  Fresno 281 

Eucalyptus  robusta,  near  Tulare,  Kingsburg  and  Fresno 282 

Eucalyptus  amygdalina,  sideroxylon,  gunnii,  near  Tulare 283 

SUMMARY  OF  RESULTS  OF  INVESTIGATION  AND  CONCLUSIONS—  285 

EUCALYPTUS  CULTURE  METHODS  (Reprints  from  Bulletin  196) 289 

Introduction 289 

Eucalyptus  for  timber,  fuel,  oil,  bee  pasture 290 

Potash  in  eucalypts 293 

Planting,  cultivation,  and  methods  of  growing  eucalypts 294 

DESCRIPTION   OF    SPECIES   OF   EUCALYPTS    (Reprints    from   Bulletin 

196;  also  from  Messrs.  Kinney  and  von  Mueller) 298 

Eucalyptus    amygdalina    298 

Eucalyptus  botryoides,  with  photograph 299 

Eucalyptus  corynocalyx,  with  photograph 299 

Eucalyptus   cornuta 303 

Eucalyptus   crebra,  with  photograph 303 

Eucalyptus  globulus,  with  photograph 303 

Eucalyptus  gunnii 307 

Eucalyptus  robusta,  with  photograph 307 

Eucalyptus  rostrata,  with  photograph 309 

Eucalyptus  rudis,  with  photograph , 311 

Eucalyptus  sideroxylon,  with  photograph 313 

Eucalyptus  tereticornis,  with  photograph 313 

Eucalyptus  viminalis,  with  photograph 316 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  California,  Davis  Libraries 


http://www.archive.org/details/toleranceofeucal225loug 


TOLERANCE  OF  EUCALYPTUS  EOR  ALKALI 

By  R.  H.  Loughridge. 


During  the  past  few  years  the  interest  in  Eucalyptus  growing  has  been 
widespread  over  the  State,  because  of  the  increasing  scarcity  of  timber 
trees  for  commercial  purposes,  the  prospect  of  "splendid  financial 
returns ' '  to  growers  after  the  lapse  of  fifteen  or  more  years  and  because 
of  the  special  adaptation  of  California  climate  and  soil  to  that  group 
of  trees. 

It  goes  without  saying  that  for  all  plants  and  trees  the  better  the 
soil  the  better  the  growth,  and  Eucalyptus  is  not  an  exception.  It 
attains  its  most  rapid  growth  in  a  loose  loam  soil  that  contains  an 
abundance  of  the  plant  food  elements,  potash,  lime,  magnesia,  iron, 
phosphoric  acid,  and  especially  of  humus  with  high  nitrogen  content; 
a  soil  of  ten  or  more  feet  in  depth  in  which  root  development  and  ac- 
tivity may  be  free  and  unrestricted  by  hardpan,  bedrock,  gravel,  or  high 
water-table ;  a  soil  having  a  good  moisture  supply  and  good  aeration ;  a 
soil  that  is  warm  and  capable  of  facilitating  bacterial  activity  in  the 
formation  of  nitrates  from  the  organic  nitrogen  of  humus.  But  lands 
of  this  nature  are  usually  far  more  valuable  for  other  cultural  purposes 
than  the  growth  of  Eucalyptus  trees,  and  for  this  reason  the  culture  of 
the  latter  on  the  large  scale  is  often  being  done  or  attempted  on  tracts 
that  seem  to  be  unfitted  for  general  farming  purposes. 

It  thus  happened  that  attention  was  called  to  the  large  tracts  of 
alkali  land,  that  occur  in  those  portions  of  the  valleys  of  the  State 
where  a  low  rainfall  and  other  conditions  have  favored  the  accumula- 
tion of  these  soluble  alkali  salts.  It  is  well  known  that  plants  both 
small  and  large  can  withstand  the  effect  of  only  certain  amounts  of 
these  salts,  and  that  they  also  vary  in  their  power  of  tolerance,  some 
being  very  sensitive  and  others  quite  immune  except  to  very  large 
amounts.  Citrus  trees,  for  instance,  seem  to  be  seriously  affected  by 
2,500  pounds  of  common  salt  per  acre,  while  grapes  grow  fairly  well  in 
many  times  that  amount. 

Recognizing  this  fact  the  eucalyptus  grower  quickly  appealed  to  this 
station  for  information  as  to  the  amount  of  alkali  the  eucalyptus  would 
tolerate  while  making  good  growth.  It  has  unfortunately  happened 
that  while  we  have  for  the  past  fifteen  years  made  observations  regard- 
ing very  many  other  cultures,  such  as  grain  crops,  alfalfa,  fruit  trees, 
etc.,  only  casual  attention  has  been  given  to  the  Eucalyptus;  in  fact, 
the  only  analysis  of  alkali  in  a  soil  growing  these  trees  which  we  were 


248  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 

able  to  find  was  that  from  the  Tulare  Station ;  and  a  search  of  publica- 
tions from  other  states  and  countries  gave  no  record  of  such  an  exam- 
ination, the  various  writers  on  the  planting  and  growing  of  eucalypts 
having  failed  to  note  the  alkali  side  of  the  question.  Even  at  the 
Tulare  Station,  where  quite  a  number  of  large  Eucalyptus  trees  are 
growing,  no  examination  was  considered  important  until  the  question 
of  tolerance  came  from  growers. 

We  then  took  up  the  task  of  trying  to  ascertain  as  near  as  possible 
the  alkali  tolerance  of  the  chief  species  of  the  tree,  working  thereto  in 
several  directions;  first  to  ascertain  the  maximum  amount  in  which  the 
trees  were  growing  and  doing  well,  and  the  minimum  amount  of  each 
salt  where  they  had  succumbed  to  the  effects  of  the  alkali  alone ;  second, 
to  examine  new  plantations  and  nurseries  in  which  the  alkali  was  plainly 
present ;  and  third,  to  select  a  large  alkali  spot  in  which  to  plant  several 
of  the  more  important  species  in  alkali  of  varying  strengths. 

Mr.  Frank  E.  Johnson,  assistant  in  the  soil  laboratory,  was  intrusted 
with  the  work  of  visiting  the  plantations  of  eucalypts  in  the  alkali 
regions  of  the  State,  noting  tree  conditions  and  collecting  soils  for 
examination.  He  also  made  the  greater  number  of  alkali  analyses 
that  are  given  in  this  report. 

The  identification  of  species  from  samples  brought  in  was  largely 
done  by  Prof.  H.  M.  Hall,  botanist  of  this  station ;  unfortunately,  it  was 
impossible  to  recognize  the  species  of  many  of  the  specimens,  and  the 
results  of  the  examinations  of  soils  in  which  these  were  growing  were 
thus  of  no  practical  value  and  are  omitted  from  this  report. 

The  work,  however,  upon  which  we  relied  chiefly  in  our  study  of  the 
alkali  tolerance  of  the  eucalypts  was  with  seedlings  planted  in  the 
Tulare  Station,  and  this  was  carried  on  under  the  supervision  of  the 
foreman,  J.  T.  Bearss. 

CONDITIONS  TO  BE  MET  IN  THESE  INVESTIGATIONS. 

The  investigation  of  the  tolerance  of  alkali  on  the  part  of  any  culture 
is  a  matter  of  great  difficulty  because  of  the  impossibility  of  eliminating 
the  many  causes  other  than  alkali  that  might  produce  injury,  disease 
and  death,  such  as  insects,  shallowness  and  bad  physical  conditions  in 
the  soil,  improper  water  supply,  climatic  troubles,  etc.  All  of  these 
must  be  considered  when  studying  the  question,  and  they  make  the 
effort  to  arrive  at  correct,  or  even  approximately  correct  conclusions, 
especially  difficult.  To  these  must  be  added  the  irregular  and  broad 
extension  of  the  root  systems,  and  the  irregular  distribution  in  the  soil, 
both  downward  and  laterally,  of  the  alkali  salts  and  of  each  individual 
salt ;  these  could  in  large  measure  be  controlled  or  eliminated  by  planting 
in  a  large  number  of  boxes  of  proper  sizes  in  which  certain  percentages 
of  alkali  salts  are  thoroughly  intermixed  with  the  soil,  the  roots  held 


Bulletin  225]        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI.  2-49 

in  contact  with  the  alkali,  and  water  conditions  kept  in  control,  but  even 
this  would  be  attended  with  uncertainties  and  would  have  to  be 
extended  over  several  seasons,  before  conclusions  could  be  definitely 
reached. 

In  the  field  examinations,  therefore,  we  have  found  it  unsafe  to  claim 
that  a  tree  or  plant  has  been  injured  or  killed  by  the  amount  of  alkali 
in  its  soil  (except  of  course  the  amount  be  enormous),  unless  corrobo- 
rated by  a  number  of  instances  where  soil  conditions  are  perfect.  We 
can  only  ascertain  the  highest  amount  of  each  particular  alkali  salt  or 
combination  of  salts  occurring  in  the  upper  few  feet  of  the  soil  in  which 
the  plant  or  tree  is  apparantly  unharmed,  thus  fixing  for  the  time  being 
its  maximum  of  tolerance;  this  maximum  may  subsequently  be  raised 
by  other  observations.  If  other  individuals  of  the  same  species  are 
suffering  or  injured  in  soils  containing  less  amounts  of  the  salts  than 
the  supposed  maximum,  then  we  must  attribute  the  injury  to  other 
causes  than  alkali  alone. 

A  very  large  number  of  examinations  are  therefore  necessary  to 
ascertain  this  maximum  because  of  the  uncertainty  of  the  strength  of 
alkali  in  each  locality.  Thus,  in  this  Eucalyptus  investigation,  we 
have  made  several  hundred  analyses  to  ascertain  the  amount  and  com- 
position of  the  alkali  salts  under  as  many  trees. 

If  alkali  consisted  of  but  one  salt  the  study  of  toleration  would  be 
quite  simple;  but  we  find  that  there  are  several  salts,  each  having  a 
different  effect  and  behavior,  which  tend  to  complicate  the  study  with 
reference  to  plants  and  trees.  These  salts  are  sulfate  of  soda  or  glaubers 
salt,  carbonate  of  soda  or  sal  soda  and  chlorid  of  sodium  or  common  salt, 
together  with  more  or  less  of  sulfates  of  magnesia  and  lime  and  nitrates 
of  soda  and  magnesia.  The  three  first  named  are  however  recognized 
as  the  alkali  salts,  and  are  alone  considered  when  alkali  is  mentioned. 

Difference  in  Action  of  Alkali  Salts. — Each  salt  has  its  influence  on 
plant  growth,  but  in  different  degrees  of  intensity  and  in  nature  of 
action ;  and  this  of  course  still  further  complicates  the  study  of  tolerance 
on  the  part  of  the  plant.  The  sulfates  seem  to  be  rather  inert  for  any 
direct  injury ;  being  very  soluble  in  water,  they  probably  enter  the  plant 
cells  with  solutions  of  plant  food,  and  if  in  very  large  amounts  interfere 
with  the  proper  assimilation  and  action  of  the  food ;  or  by  accumulation 
as  a  soil  crust  they  may  interfere  with  the  functions  of  the  plant  roots. 

Common  salt  is  with  some  cultures  probably  the  most  to  be  feared  of 
the  three  alkali  salts,  not  so  much,  perhaps,  because  of  any  direct  action 
on  the  plant,  but  because  of  its  injurious  influence  on  important  micro- 
organisms in  the  soil,  its  action  through  a  greater  depth  than  the  car- 
bonate, its  action  when  in  larger  amounts  in  preventing  a  normal  water 
supply  and  consequent  starvation  of  the  plant,  and  in  the  fact  that  the 


250 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


injury  can  only  be  prevented  by  its  removal  from  the  soil  by  thorough 
leaching. 

The  carbonate  of  soda  is  strongly  caustic  or  corrosive,  attacking  the 
root-hairs  and  the  tender  bark  of  the  root  crown,  girdling  it  and  pre- 
venting the  rise  of  sap  into  the  plant.  It,  therefore,  acts  most  energet- 
ically near  the  surface  of  the  soil,  and,  fortunately,  may  be  here  easily 
neutralized  by  conversion  into  sulfate  on  the  application  of  gypsum,  as 
Jong  ago  recommended  in  the  publications  of  this  station. 

These  salts  occur  together  in  greatly  varying  proportions  through 
the  soil  column  downward  and  laterally  because  of  differences  in  the  ease 
with  which  they  move  from  point  to  point ;  the  sulfates  because  of  their 
crystalline  form  rise  rapidly  in  the  soil  and  with  the  chlorids  occur 
chiefly  in  the  upper  foot;  while  the  carbonate  occurs  more  generally 
diffused  downward.  The  effect  on  the  plant  is  therefore  largely  in- 
fluenced by  the  amount  of  each  salt  in  the  soil  and  their  relative  pro- 
portion; thus  forming  a  problem  the  more  complex  as  the  effects  of 
the  salts  depend  largely  upon  the  physical  nature  of  the  soil. 
•  Irregular  Distribution  of  Alkali. — The  irregular  distribution  of  the 
alkali  as  a  whole  and  of  each  salt  throughout  the  soil  was  an  especial 
disturbing  element  in  this  investigation.  Not  only  is  this  the  case  in 
a  vertical  column  of  four  or  more  feet,  but  we  find  the  same  irregular 
distribution  in  a  horizontal  section.  This  is  shown  in  the  analyses  of 
samples  from  the  cross-section  of  an  alkali  plot  in  the  Tulare  Station 
made  a  number  of  years  ago  by  C.  A.  Colmore,  and  reported  in  the 
report  of  this  station  for  1902 : 


Percentage  Composition  of  Salts  in  an  Alkali  Spot. 


32  feet  from  center. 

16  feet  from  center. 

Center  of  spot. 

Depth. 

CO 

c 
s» 

a 
co 

o 

3   to 

8  ? 

a 

o 

SO 

06 
C 

¥ 

Q 

3   So 

8  ? 

a 

V 

o 

0> 

CO 

o 

02 

C 

ST 

CO 

a 

3  so 

8  ? 
! 

n 

3" 
O 

o 
s» 

First    foot    

.74 
.05 
.08 
.02 

.21 

.01 
.03 
.01 
.01 

.02 

.14 
.01 

.04 

.89 
.09 
.04 
.03 

.27 

1.02 
.36 
.05 
.05 

.37 

.01 
.01 
.01 
.01 

.01 

.17 
.03 
.01 

.05 

1.20 
.40 
.07 
.06 

.43 

1.09 
.23 
.14 

.08 

.39 

.01 
.02 
.01 
.01 

.01 

.01 
.01 
.01 

.01 

1   11 

Second   foot  

,26 

Third   foot   

Fourth    foot    

.16 

.09 

Average  

.41 

These  tables  are  more  valuable  in  illustrating  the  irregular  down- 
ward distribution  than  the  horizontal,  for  the  holes  were  dug  at  dis- 
tances of  sixteen  feet  from  each  other.  On  other  pages  of  this  bulletin 
will  be  found  a  table  and  diagram  on  which  are  shown  the  percentages 
of  alkali  found  at  distances  of  but  a  few  feet  in  all  directions,  and  which 
very  forcibly  illustrates  this  rapidly  changing  composition.     In  fact, 


BULLETIN  225]         TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI.  251 

we  believe  that  columns  of  alkali  soils  but  a  few  inches  apart  would 
show  the  same  variability  in  amount  and  composition  of  its  alkali. 

In  this  table  there  is  laterally  more  of  total  salts  and  of  chlorids  and 
somewhat  less  of  carbonates  and  sulfates  at  16  feet  from  the  center  than 
in  the  center,  while  at  32  feet  there  is  a  falling  off  in  total  salts,  sulfates, 
and  chlorids,  but  an  increase  in  the  carbonates. 

In  the  vertical  columns  the  alkali  is  concentrated  in  the  first  foot, 
but  the  carbonate  has  its  highest  percentages  in  the  second  foot. 

It  is  chiefly  this  irregular  distribution  of  each  salt  that  makes  difficult 
the  task  of  arriving  at  definite  conclusions  on  the  toleration  of  any  plant, 
and  shows  the  importance  of  taking  the  soil  samples  in  close  proximity 
to  the  plant  or  tree. 

Alkali  Exists  in  small  instead  of  very  large  Areas. — Another  condi- 
tion to  interfere  with  the  investigation  is  the  fact  that  alkali  occurs  only 
in  spots  and  of  varying  strengths.  These  spots  are  often  but  a  few 
feet  in  diameter;  hence  trees  near  together  may  be  growing  under 
entirely  different  alkali  conditions  and  the  amount  tolerated  by  one  tree 
may  not  be  the  same  that  occurs  beneath  the  others. 

This  condition  is  shown  in  the  small  tract  of  young  trees  planted  on 
the  Tulare  Station.  It  is  this  condition  that  makes  it  inadvisable  to 
present  the  alkali  percentages  on  a  map,  for  small  spots  or  areas  are 
usually  far  apart  with  larger  intermediate  tracts  of  land  that  may  be 
nearly  or  quite  free  from  alkali.  Of  course  in  some  sections  of  the 
State,  especially  in  the  trough  connecting  the  lakes  that  lie  in  the  upper 
part  of  the  San  Joaquin  Valley,  the  alkali  is  quite  continuous,  but  even 
then  in  varying  amounts  from  one  hundred  thousand  pounds  per  acre 
in  six  feet  to  so  low  an  amount  as  to  insure  crop  productiveness. 

To  this  fact  combined  with  the  irregular  distribution  of  the  salts  in 
amounts  and  kinds  is  due  the  great  difficulty  in  selecting  proper  soil 
samples. 

Movement  of  Alkali  in  the  Soil. — Another  factor  to  be  regarded  in  the 
problem  of  tolerance  is  the  movement  or  rise  and  fall  of  alkali  salts  at 
different  seasons  of  the  year  due  to  water  evaporation.  In  the  alkali 
regions  of  California  there  are  really  but  two  seasons,  the  winter  or  wet 
season,  from  November  to  April,  during  which  time  the  entire  yearly 
precipitation  occurs,  and  the  summer  or  dry  season,  when  there  is  prac- 
tically no  rainfall.  The  salts  of  alkali  being  extremely  soluble  in  water, 
therefore,  are  dissolved  in  winter  rain  and  pass  downward  with  the  water 
to  depths  dependent  on  the  physical  condition  of  the  soil  and  the  amount 
of  rain,  but  usually  three  or  four  feet. 

During  this  wet  period  of  course  the  roots  near  the  soil  surface  are 
relieved  of  the  influence  of  the  alkali  and  may  attain  good  development 
before  the  hot  rainless  summers  produce  an  upward  capillary  movement 


252  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

of  the  water  and  alkali,  and  a  concentration  of  the  latter  in  the  upper 
foot  or  two,  where  damage  is  done  to  the  roots. 

All  of  these  conditions  must  be  considered  when  we  study  the  plant, 
together  with  the  annual  or  seasonal  rainfall  as  indicating  to  what 
depth  the  water  may  percolate  and  carry  the  salts  with  them.  A 
precipitation  of  an  inch  of  rain  will  penetrate  4  or  5  inches  in  a  loam 
soil  and  less  in  a  clay  soil.  A  continuous  fall  of  5  inches  of  rain  would 
therefore  wash  the  alkali  down  through  a  depth  of  probably  18  or  20 
inches.  Should  this  be  followed  by  a  warm,  protracted  dry  spell  the 
alkali  water  would  doubtless  rise  by  capillarity  to  be  again  carried  down 
by  subsequent  rains.  This  rise  and  fall  of  the  alkali  salts  produces  a 
critical  period  in  the  life  and  growth  of  the  young  trees  with  their  root 
systems  limited  in  length  and  spread,  and  subject  to  attack  by  the  alkali 
and  more  especially  by  the  caustic  carbonate.  Could  the  alkali  be  kept 
down  for  some  feet  in  the  soil  until  the  young  roots  become  strong,  well 
developed  and  with  a  comparatively  thick  bark  the  tree  may  survive 
alkali  of  quite  a  strength.  There  is  but  little  doubt  that  many  eucalypti 
now  growing  in  strong  alkali  soils,  have  been  enabled  to  secure  good, 
strong  root-development  during  the  time  that  the  alkali  was  several  feet 
below  the  surface  and  thus  to  become  partly  if  not  wholly  immune  to  its 
effect  when  subsequently  concentrated  near  the  surface.  "When  the 
tender  roots  reach  below  the  zone  of  alkali  the  tree  is  quite  safe  from 
injury.  This  point  of  view  is  emphasized  by  the  native  mesquit  which 
we  find  growing  in  the  strongest  of  alkali  lands,  its  thick  and  deep-lying 
roots  being  well  protected  against  the  influence  of  alkali  by  thick,  tough 
bark. 

This  uncertainty  regarding  the  movement  of  the  several  salts,  and 
this  irregularity  of  alkali  composition  and  distribution,  was  one  of  the 
chief  sources  of  trouble  in  studying  the  effect  on  trees  and  plants,  for 
not  until  an  analysis  has  been  made  of  the  alkali  content  of  the  soil  can 
we  judge  of  its  strength  and  percentage  composition. 

Development  of  the  Eucalyptus  Boot  System.-^In  addition  to  the 
climatic  and  other  difficulties  to  be  met  in  the  study  of  the  influence  of 
the  alkali  salts  upon  the  life  and  growth  of  the  eucalypts  we  have  that 
of  the  rapid  development  of  the  root  systems  of  the  tree ;  this  practically 
limits  the  time  for  observation  to  the  earliest  stages  of  growth  when 
the  young  roots  are  within  the  alkali  zone. 

The  Eucalyptus  tree  develops  its  root  system  very  rapidly  as  it  grows 
from  the  young  plant  to  the  large  tree.  It  is  a  general  supposition  in 
California  that  the  tap  root  reaches,  if  unimpeded,  to  a  depth  below  the 
surface  of  the  soil  equal  to  the  height  of  the  tree  above  ground ;  this  in 
old  trees  would  be  fully  100  feet  in  alluvial  lands.  Depths  of  60  feet 
have  been  reported  from  southern  California.  The  lateral  extension 
of  the  roots  is  well  known  to  be  very  great,  a  root  one  fourth  of  an  inch 


Bulletin  225]        TOLERANCE   OF   EUCALYPTI'S   FOR    ALKALI.  253 

thick  having  been  observed  by  us  in  an  orchard  near  Riverside,  at  a 
distance  of  75  feet  from  the  tree  and  evidently  its  extension  was  fully 
25  feet  further.  This  large  lateral  development  of  the  Eucalyptus 
roots,  where  the  trees  have  been  planted  as  wind  breaks  or  for  ornament, 
is  a  well  known  source  of  danger  to  adjacent  fruit  orchards  because  of 
their  great  absoption  of  soil  moisture ;  in  some  cases  deep  trenches  have 
been  dug  to  cut  the  Eucalyptus  roots  and  protect  the  orchard  trees. 

The  Eucalyptus  Timber  Corporation  of  Tulare  County  has  made 
observations  of  the  root  development  of  young  trees  and  some  of  the 
results  as  contained  in  a  pamphlet  of  the  company  are  here  given  : 


Age  of  tree. 

Height  of  tree. 

Depth  of  tap  root. 

15J  months — 

13  feet   6  inches 

7  feet 

6  feet  11  inches 

8  feet 

16  feet   6  inches 

6     months 

7  feet  11  inches 

6    months __      _ __ 

8  feet 

6     months 

8  feet   1  inch 

The  downward  development  is  even  greater  in  the  above  young  trees 
than  they  are  usually  credited  with ;  and  if  the  same  ratio  of  increase  is 
maintained  a  tree  100  feet  high  would  have  a  tap  root  from  110  to  123 
feet  below  the  surface  of  the  ground.  This  is  not  to  be  greatly  doubted 
where  depth  of  soil  strata  permits,  for  this  deep  penetration  of  the  roots 
of  other  trees,  both  ornamental  and  orchard,  as  well  as  of  plants  and 
grasses  in  California  soils  is  of  common  observation,  as  reported  in 
previous  publications  of  this  Station.  The  roots  of  wheat,  barley,  and 
the  California  poppy  (EscJischoltzia  calif ornica)  have  been  followed  to 
depths  of  thirteen  feet  in  the  loam  soil  of  the  University  Farm  at  Davis, 
Yolo  County,  California. 


254  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


TEST  PLOT  POR  EUCALYPTUS  SEEDLINGS:  TULARE  STATION. 

The  critical  period  in  the  life  of  any  plant  that  has  been  placed  in  a 
soil  is  when  it  is  very  young  and  when  its  root  system  is  very  delicate 
and  susceptible  to  injury,  and  is  limited  in  its  development  to  the 
surface  foot  of  the  soil.  When  to  the  ordinary  dangers  of  improper 
temperature  and  moisture,  poor  aeration,  severe  soil  texture  and  defi- 
ciency in  plant  food,  is  added  that  of  the  effect  of  alkali,  and  especially 
of  carbonate  of  soda,  the  life  of  the  plant  is  still  more  endangered 
because  of  the  action  of  these  salts  on  the  extremely  tender  root-hairs 
and  bark  of  the  young  roots.  As  the  plant  grows  older  the  roots  become 
more  woody  near  the  soil  surface  and  are  less  susceptible  to  injury,  and 
they  also  extend  to  greater  depths  and  with  a  greatly  enlarged  and 
broadened  root  system ;  the  delicate  tips  or  newest  growing  parts  of  the 
roots  are  thus  farther  and  farther  from  the  influence  of  the  alkali  which 
usually  exists  only  in  the  upper  four  feet.  If,  then,  the  young  plant 
can  survive  the  first  year  or  two  in  an  alkali  soil  there  is  but  little  doubt 
of  its  ultimate  success. 

An  old  tree  growing  in  an  alkali  spot  is  a  proof  either  that  the  alkali 
contained  in  the  soil  around  its  base  was  not  sufficient  to  injure  the 
roots  when  the  tree  was  very  young,  or  that  the  alkali  had  been  kept 
below  the  roots  by  some  system  of  irrigation  or  cultivation  until  their 
broad  expansion  and  growth  downward  had  carried  them  out  of  danger ; 
for  it  is  usually  the  alkali  in  the  upper  foot  or  two  of  soil  that  causes 
injury.  In  this  report  we  have  therefore  laid  greater  stress  on  the 
experiments  with  Eucalyptus  seedlings  planted  in  a  spot  of  alkali  soil 
in  the  Tulare  Station  than  upon  observations  upon  older  trees. 

Distribution  of  Alkali  in  Soil  of  Eucalyptus  Plot. — A  spot  of  sup- 
posedly very  strong  alkali  was  chosen  near  the  southwest  corner  of  the 
Tulare  Station  tract  on  which  to  test  the  effect  of  alkali  of  different 
strengths  upon  young  eucalypts  of  the  different  species  chiefly  grown  in 
this  State.  In  previous  years  eucalypts  had  been  planted  here,  and 
some  of  these  still  remain  around  the  spot,  but  many  had  died  from 
various  causes.  This  spot  embraced  an  irregular  area  of  about  150  by 
100  feet,  and  in  its  center  the  soil  was  covered  with  a  coating  of  alkali 
salts  and  was  entirely  bare  of  vegetation.  A  preliminary  determination 
of  the  strength  and  distribution  of  the  alkali  was  made  by  the  analyses 
of  nearly  one  hundred  four-foot  soil-columns  taken  at  distances  of  ten 
feet  in  each  direction.  The  results  in  percentages  are  given  in  the 
accompanying  table ;  and  also  in  the  diagram,  in  which  is  also  presented 
many  subsequent  analyses  which  were  made  of  soils  taken  very  close  to 
the  young  trees  that  had  been  planted.     The  diagram  is  shaded  to  show 


Bulletin  225 J        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI.  255 

at  a  glance  the  varying  intensities  of  total  salts;  the  large  numbers 
represent  approximately  the  number  of  pounds  of  alkali  per  acre  in  a 
depth  of  four  feet  in  each  shaded  area. 

Alkali  Salts  in  the  Soils  of  the  Eucalyptus  Test  Plot,  Tulare  Station. 

Taken  four  feet  in  depth  at  distances  of  ten  feet  in  each  direction. 

Sulfates   .048        .070        .110        .192         .257         .395        .114        .157  .130        .065        .072 

Carbonates    .007        .007        .007        .007        .014        .005        .005        .005  .005        .006        .005 

Chlorids    .028         .009        .005        .005        .019        .074         .005         .028  .019        .023         .009 

Totals    .083         .084         .122         .204         .290         .474         .124         .190  .154         .094         .086 

Sulfates  .058        .076         .048         .174        .290        .257         .425        .193  .104         .137         .094 

Carbonates    .005        .003        .007        .009        .009        .012        .002        .010  .009        .005        .007 

Chlorids    .005        .009        .009         .009        .005        .009         .009        .005  .005        .009        .009 

Totals   .068         .088        .164        .252         .304         .278         .436        .208  .118        .151         .110 

Sulfates   .078        .088         .170         .397         .347         .375        .281         .279  .140        .141         .138 

Carbonates    .007        .003        .007        .002        .005        .004        .009        .005  .007        .005        .005 

Chlorids    .005        .005        .009        .005         .009        .009        .014         .019  .019        .028        .009 

Totals    .090         .096         .186         .404         .361         .388         .304         .303  .166         .174         .152 

Sulfates  .111         .130        .227         .482         .411         .520         .305        .234  .168        .118        .114 

Carbonates    .002        .005        .007        .007        .009        .003        .012        .009  .009        .005        .005 

Chlorids    .009        .009        .009         .023         .009         .009        .028         .023  .019         .009         .005 

Totals    .122         .144         .243         .512         .414         .532         .345         .266  .196         .132         .124 

Sulfates  .110        .116        .191        .226        .460        .330        .331        .184  .164 

Carbonates   .003        .007        .010        .009        .009        .009        .005        .005  .003        Trees 

Chlorids    .009         .005        .005         .009        .009         .009        .019        .009  .009 

Totals   .122         .128        .206        .244         .478        .348        .355         .198  .176 

Sulfates     .-     .168        .184         .148        .152         .222         .318        .187         .193  .  .165 

Carbonates    .003        .005        .009        .010        .011        .012        .008        .002  .002       Trees 

Chlorids    .009         .009        .009        .009         .009        .009        .009        .009  .009 

Totals   .170        .198         .166         .171         .232         .339        .204         .204  .176 

Sulfates   .103        .123         .167         .182         .186         .119        .116        .111 

Carbonates   .004        .003        .004        .005        .004        .004        .005        .002  Trees 

Chlorids    .005        .009        .009        .005        .009        .009        .009        .009 

Totals   .112         .135         .180        .192         .199        .132         .130        .122 

Sulfates  .195        .090        .110        .107        .116        .122 

Carbonates    .003        .004        .005        .006        .005        .005       Large  trees 

Chlorids    .009        .009        .009        .009        .009        .009 

Totals   .208         .104         .124         .122         .130        .136 

Sulfates  .     .168        .227        .116        .122  .163 

Carbonates   .009        .009        .006        .005  .002        Large  trees 

Chlorids    .009        .009        .014        .028  .009 

Totals   .186        .245         .136         .155  .174 

A  spot  of  maximum  intensity  is  seen  near  the  center  of  the  plot  where 
the  percentage  is  .63  as  an  average  of  the  four-foot  column  of  soil,  but 
thence  in  all  directions  the  percentage  is  less  and  the  alkali  diminishes 

with  great  irregularity  out  to  the  edges  of  the  tract.  The  outlines  of 
each  area  of  intensity  are  also  peculiarly  curved. 

The  table  and  the  diagram  illustrate  very  forcibly  the  following  facts, 


256 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


often  brought  out  with  emphasis  in  this  and  former  publications  of  this 
station : 

1.  That  the  distribution  of  alkali  and  of  its  salts  in  any  plot  is  very 
irregular. 

2.  That  great  differences  both  in  quality  and  in  amount  exist  at 
distances  of  but  a  few  feet  or  even  less. 

3.  That  a  plant  may  live  and  grow  in  one  part  of  an  alkali  spot  and 
yet  be  killed  by  stronger  alkali  if  planted  but  a  few  feet  distant. 

4.  That  an  analysis  giving  the  composition  of  the  soil  at  one  point  of 
an  alkali  spot  may  fail  utterly  to  represent  the  amount  of  alkali  of  other 


Fig.   1. — Diagram    showing   the    distribution   and   intensity    of   alkali   in    the 
Eucalyptus  plot ;  Tulare  Station. 

portions,  and  can  not  therefore  be  relied  on  when  the  question  of  treat- 
ment or  crop  production  is  to  be  considered. 

5.  That  it  is  a  grave  mistake  to  outline  large  regions  on  a  map  as 
having  each  a  definite  percentage  of  alkali,  for  such  regions  mostly 
contain  large  tracts  of  land  practically  free  from  alkali  which  might 
thus  be  popularly  regarded  as  unsuitable  for  crop  production. 

6.  That  the  examination  of  an  alkali  spot  downward  is  important 
in  order  to  ascertain  whether  the  alkali  extends  to  great  depths  as  in 
some  parts  of  California,  or  to  not  more  than  three  or  four  feet  as  is 
usually  the  case. 


Bulletin  225]        TOLERANCE   OF   EUCALYPTUS   FOR    ALKALI.  257 

The  area  of  strong  alkali  being  limited  it  was  determined  to  make 
plantings  of  but  few  of  the  more  important  varieties  grown  in  this 
State,  and  we  chose  the  crebra,  corynocalyx,  cornuta,  globulus,  rudis, 
rostrata,  and  tereticornis,  small  seedlings  of  which  were  obtained  from 
the  Fancher  Creek  nurseries  at  Fresno.  These  were  planted  by  the 
foreman  of  the  Tulare  Station  at  distances  of  six  feet  in  rows  which 
were  ten  feet  apart,  and  received  two  irrigations  during  the  season. 
These  were  not  planted  in  the  rows  from  which  soils  had  been  taken  for 
the  original  examination,  but  between  them,  and  it  therefore  became 
necessary  to  take  other  samples  of  soil  very  close  to  the  seedlings  to 
ascertain  true  alkali  conditions  around  the  roots  at  the  end  of  the 
season  when  the  effect  of  the  alkali  was  to  be  noted. 

It  was  not  thought  necessary  to  examine  the  soil  of  each  and  all  of 
the  seedlings,  and  only  typical  ones  of  each  of  the  species  were  analyzed, 
the  results  being  given  in  the  special  discussion. 


258 


UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 


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BULLETIN  225]        TOLERANCE   OF   EUCALYPTUS   FOB   ALKALI. 


259 


EFFECT  OF  ALKALI  SALTS  UPON  VARIOUS  SPECIES  OF 

EUCALYPrS. 

At  the  end  of  the  first  season,  the  condition  and  height  of  each  plant 
in  each  species  was  ascertained  and  from  these  a  chart  (No.  2)  prepared 
showing  the  relative  heights ;  the  amount  of  carbonate  of  soda  and  that  of 
total  alkali,  given  in  pounds  per  acre  in  a  depth  of  three  feet  very  near 
certain  seedlings,  is  also  shown  on  the  chart,  the  sulfates  and  chlorids 
being  omitted  as  they  do  not  seem  to  have  produced  any  injurious  effects. 

The  total  number  of  seedlings  planted  was  244,  and  thirty-nine  of 
these  or  about  sixteen  per  cent  died,  presumably  from  the  effects  of 
alkali.  A  close  examination,  however,  showed  that  the  greater  number 
were  dwarfed  or  otherwise  injured  in  comparatively  small  percentages 
of  alkali  salts,  and  that  the  injury  was  due  doubtless  to  a  combination 
of  hurtful  conditions  rather  than  to  alkali  alone.  The  result  empha- 
sizes the  importance  of  either  eliminating  from  the  soil  all  of  such  condi- 
tions or  of  not  attempting  to  grow  good  trees  on  such  poor  land.  The 
following  table  presents  a  general  statement  of  the  number  of  seedlings 
of  each  species  that  during  the  first  season  reached  heights  of  48  inches, 
from  36  to  48,  from  24  to  36,  from  12  to  24,  and  less  than  12  inches  and 
the  number  that  died : 


Number 
planted. 

Number   within    different   heights. 

Dead. 

48  inches.       36-48. 

24-36. 

12-24. 

1-12. 

Number. 

Per  cent. 

! 

E.   comma  27 

5                 10 

3 
19 

8 
8 

22 
5 

12 

7 

7 
6 

4 

3 

25.9 

E.  corynoealyx 

E.  crebra  _.    _.    _ 

54 
25 

28 

2 

3 

22 

1 

11 

1 

11.0 
24  0 

E.   globulus 

15 

17 

12 

2 

14  3 

E.   rostrata 54 

2 

10 

8 

2 

5.6 

E.  rudis 25 

E.   teretieornis 

31 

1 

2 

12 

38.7 

Eucalyptus  teretieornis  suffered  more  than  other  species,  38.7  per 
cent  of  its  seedlings  having  died  though  planted  in  a  soil  containing 
less  alkali  than  some  of  the  others ;  the  rudis  suffered  least  of  all,  none 
of  its  seedlings  having  died.  The  rostrata  lost  but  5.6  per  cent  of  its 
large  number  of  seedlings. 

In  the  following  pages  we  give  the  results  of  the  investigations  thus 
far  obtained,  the  amount  of  alkali  salts  under  the  respective  trees  or 
plants  and  a  discussion  of  each  of  the  several  species  tested,  and  we  have 
endeavored  to  draw  from  the  mass  of  figures  some  conclusions  as  to  the 
tolerance  of  alkali  salts  on  the  part  of  the  Eucalyptus. 


2— bul  225 


260 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


EFFECT  OF  ALKALI  SALTS  UPON  EUCALYPTUS  CORYNOCALYX. 

Investigations  with  Eucalyptus  corynocalyx  were  chiefly  made  in  the 
special  alkali  plot  of  the  Tulare  Experiment  Station,  where  54  seedlings 
were  planted  in  two  rows  at  distances  of  six  feet,  the  rows  being  ten 
feet  apart.  Some  of  the  trees  were  in  strong  alkali  but  the  greater 
number,  at  either  end  of  the  rows,  were  planted  in  soils  containing  com- 
paratively small  amounts  of  the  salts. 

The  maximum  height  reached  by  the  seedlings  in  the  first  year  was 
only  30  inches,  in  a  soil  with  but  little  alkali  and  also  in  one  containing 
.31  per  cent  of  salts.  Seven  of  the  trees  died,  several  of  them  from  other 
causes  than  alkali ;  one  reached  a  height  of  only  8  inches,  nineteen  from 
12  to  24  inches,  and  twenty-five  above  that  height,  two  of  the  latter  being 
48  inches. 

In  other  parts  of  the  State  Mr.  Johnson  found  but  two  trees  that 
could  be  identified  as  corynocalyx;  one  near  Hanford  was  growing  in  a 
soil  that  had  only  saltgrass  on  it  before  being  brought  into  cultivation. 
It  was  three  years  old,  25  feet  high,  and  looked  thrifty  though  there 
was  some  yellowing  of  the  leaves.  The  tree  from  near  Fresno  was  two 
years  old  and  3  feet  tall,  and  had  had  good  care,  though  showing  consid- 
erable effect  of  the  alkali.  It  stood  in  a  small  tract  where  grapevines  had 
failed  to  grow.  The  tips  of  its  branches  and  leaves  were  reddish,  and 
the  tree  rather  stunted ;  hardpan  underlaid  the  surface  at  about  4  feet. 

E.  CORYNOCALYX  IN  Ai  KALI  SOIL. 


H 

M 

«• 

X 

cr 

a 

B* 

CO 

U 

30 

14 

24 

4 

18 

8 

18 

6 

6 

12 

8 

13 

8 

Ft 

— 

25 

- 

•- 

3 

Condition. 


Percentage  in  soil. 

GO 


Tulare  Station,  S  foot  depth 
Two  lowest  leaves  red;   others 

good    

Two  lowest  leaves  red;   others 

good    

Leaves   of   lower  half   spotted 

and   dying   

Lower  leaves  affected  

Dead  

Dead  

Dead  

Other  Localities,  4  feet  deep. 
Hanford,  some  yellow  leaves.... 
Fresno,    stunted   


.2.3 

.17 

.05 
.11 

.08 
.20 
.17 


.05 


Pounds  per  acre  in  3  feet. 


Sulfate 
of  soda. 


Carbo- 
nate of 


.31 

.24 

.10 
.20 
.14 
.25 
.23 


30,000 
20,400 

6,000 
13,200 

9,600 
24,000 
20,400 


.16     12,800 
.08   j    8,000 


4,800 

4,800 

4,800 
9,600 
8,000 
4,800 
4,800 


Chlorid 

of 
sodium. 


Total 
salts. 


2,400       37,200 


3,600       28,800 


1,200 
1,200 
1,200 
1,200 
2,400 


12,000 
24,000! 
18,800 
30,000 
27,600 


25,600 
12,800 


A  glance  at  the  table  will  show  that  the  sulfates  have  had  but  little 
to  do  with  the  injury  to  the  young  trees,  as  the  greatest  height  reached 
was  in  a  soil  with  the  maximum  of  .25  per  cent  of  sulfates  (30,000 
pounds)  in  three  feet  depth  per  acre. 


Bulletin  225]         TOLERANCE  OF  EUCALYPTUS  FOR  ALKALI. 


261 


The  results  with  the  young  seedlings  at  Tulare  were  not  at  all  satis- 
factory, for  they  attained  their  greatest  height  in  the  highest  amount 
of  sulfates  and  of  common  salt  and  in  the  same  amount  of  carbonate  of 
soda  that  occurs  in  the  soil  in  which  the  seedling  died.  The  corynocalyx 
will  clearly  withstand  the  effects  of  as  much  as  .04  per  cent  of  either 
common  salt  or  carbonate,  the  equivalent  of  4,800  pounds  per  acre  in 
3  feet,  and  is  dwarfed  by  a  larger  amount  if  allowed  to  remain  around 
the  roots.  It  grew  only  18  inches  high  the  first  year  in  presence  of 
.08  per  cent  of  carbonate  of  soda;  this  is  equivalent  to  about  9,600 
pounds  per  acre  in  three  feet  depth.  The  lower  leaves  showed  the 
effect  of  the  alkali.  Much  depends  upon  the  distribution  of  the  several 
salts  in  the  soil  column,  for  in  this  case  an  examination  showed  that  the 
carbonate  of  soda  and  the  sulfates  were  confined  chiefly  to  the  third 
foot,  while  the  common  salt  was  in  largest  amount  in  the  upper  two  feet. 

The  older  trees  in  other  localities,  as  shown  in  the  table,  have  yielded 
some  interesting  results  from  the  examination  of  their  soils.  The 
samples  of  soil  were  taken  to  depths  of  four  feet,  and  we  find  that  the 
two-year-old  tree  at  Fresno  with  a  height  of  three  feet  was  stunted  in 
presence  of  only  .02  per  cent  of  carbonate  of  soda  in  the  four  feet,  or  an 
equivalent  of  but  3,200  pounds  per  acre,  while  a  three-year-old  tree  at 
Hanford  was  25  feet  high  in  presence  of  .07  per  cent  of  carbonate  of 
soda.  The  conclusion  is  plain,  that  the  young  corynocalyx  will  not 
withstand  a  large  amount  of  carbonate  of  soda  unless  the  alkali  be  kept 
away  from  the  tender  roots  by  thorough  irrigation  methods ;  and  that 
after  it  gets  a  good  start  and  the  roots  are  developed  downward,  the 
amount  of  carbonate  of  soda  may  be  quite  large  without  detriment  to 
the  tree. 

Observations  in  1910.— After  the  station  was  abandoned  no  attention 
was  given  to  the  trees,  and  a  visit  to  the  plot  showed  that  ten  more  of 
the  corynocalyx  had  died,  six  were  still  barely  living  while  nineteen 
others  (chiefly  at  the  ends  of  the  rows  where  the  alkali  was  less)  had 
increased  in  height.  The  greatest  increase  in  growth  was  28  inches  at 
the  extreme  eastern  end,  and  18  inches  on  the  west.  Tree  No.  4  in  a 
soil  with  .04  per  cent  of  carbonate  of  soda  had  grown  12  inches,  while 
Nos.  11  and  14,  with  the  same  amount  of  carbonate,  had  died. 

EffECT  Of  ALKALI  ON  EUCALYPTUS  CREBRA. 

Eucalyptus  crebra  seems  to  be  one  of  the  slowest-growing  of  the 
Eucalyptus  species,  for  in  the  Tulare  Station  plot,  where  25  seedlings 
about  2  inches  high  were  planted,  the  maximum  height  reached  the  first 
year  in  good  soil  and  under  favorable  conditions  was  but  18  inches. 
Six  of  the  seedlings  died  quickly,  three  made  no  additional  growth 


262 


UNIVERSITY  OF   CALIFORNIA— EXPERIMENT   STATION. 


though  keeping  alive,  four  reached  a  height  of  six  inches,  four  a  height 
of  6  to  12  inches  while  but  five  grew  from  12  to  18  inches  high.  The 
young  seedlings  are  evidently  very  sensitive  to  the  effects  of  alkali  salts 
for  throughout  nearly  the  entire  row  the  leaves  and  the  plants  them- 
selves were  either  dead,  dying  or  dwarfed. 

Trees  Nos.  2  and  4,  growing  in  two  feet  of  sand  overlying  a  clay 
which  was  full  of  young  rootlets  were  but  two  inches  high  though  green ; 
No.  6  appeared  healthy,  had  no  dead  leaves  but  was  only  6  inches  high; 
No.  7  was  growing  in  a  better  soil,  but  its  lower  leaves  were  dead,  and 
others  becoming  reddish.  No.  9,  two  inches  in  height  was  entirely  dead ; 
No.  11  with  alkali  salts  upon  the  surface  of  the  soil  around  it  grew  10 
inches  high,  but  the  alkali  had  killed  the  lower  leaves.  No.  10,  also  sur- 
rounded by  black  alkali,  was  dying,  both  leaves  and  tips  of  limbs  being 
affected;  No.  12,  6  inches  high  was  living  but  the  leaves  and  tips  of 
limbs  were  dying  back. 

These  seedlings  just  described  were  selected  as  probably  giving  best 
results  and  their  soil  was  taken  to  depths  of  three  feet  for  alkali  exam- 
ination.    The  results  are  given  below. 

E.  crebra  in  Alkali  Soil. 


w 


Condition. 


2 

2 

4 

2 

6 

6 

12 

6 

11 

10 

7 

4 

10 

6 

9 

2 

Healthy,  but  no  growth_ 
Healthy,  but  no  growth. 
Healthy,   little  growth___ 

Leaves  curling  

Lower  leaves   dead 

Dying,  lower  leaves  dead 
Dying,  lower  leaves  dead 
Dead    


Percentage  in  soil. 


Pounds  per  acre,  3  feet. 


£5 


.03 
.03 
.07 
.04 
.08 
.05 
.10 
.08 


.01 

.05 
.00 
.02 
.01 
.01 
.01 


6,000 
4,800 
6,000 
22,800 
26,400 
16,800 
21,600 
18,000 


3,600 
3,600 
8,400 
4,800 
9,600 
6,000 
12,000 
9,600 


1,200 
6,000 
7,200 
2,400 
1,200 
1,200 
1,200 
7,200 


10,800 
14,400 
21,600 
30,000 
37,200 
24,000 
34,800 
34,800 


Eucalyptus  crebra  clearly  can  not  withstand  a  large  amount  of  alkali 
if  we  are  to  judge  from  the  above  observations;  for  the  young  seedlings 
began  to  die  in  presence  of  .20  per  cent  of  combined  salts  (equivalent 
to  24,000  pounds  per  acre  in  a  depth  of  three  feet)  even  when  the  car- 
bonate of  soda  was  less  than  where  the  tree  was  healthy.  The  greatest 
percentage  of  carbonate  of  soda  in  the  soil  of  a  healthy  seedling  was  .07, 
corresponding  to  about  8,400  pounds  per  acre  in  three  feet;  this  was 
combined  with  an  equal  amount  of  common  salt. 

In  a  row  of  eucalypts  planted  many  years  ago  just  outside  of  the 
south  fence  of  the  station  tract  there  is  a  crebra  having  a  height  of  75 
feet,  which  appears  very  healthy  though  growing  in  .11  per  cent  of 
alkali  in  four  feet  depth,  which  is  equivalent  to  about  17,600  pounds  per 


Bulletin  225]         TOLERANCE   OF   EUCALYPTUS    FOR   ALKALI.  263 

acre;  there  is  present  only  .02  per  cent  of  carbonate  of  soda  (3,200 
pounds  per  acre)  and  the  same  amount  of  common  salt.  This  is  nearly 
the  same  amount  of  carbonate  of  soda  and  total  salts  that  were  found 
with  the  healthy  seedlings  having  only  two  inches  growth;  evidently 
the  failure  of  the  latter  to  grow  was  due  to  other  causes  than  alkali,  or 
conditions  were  more  favorable  for  the  large  tree  when  it  was  young. 

Observations  in  1910. — A  year  after  the  above  observations  and  the 
abandonment  of  the  station,  further  observations  on  the  crebra  showed 
that  eleven  more  of  the  trees  had  died,  chiefly  in  the  region  of  strong 
alkali  that  was  covered  by  a  dense  growth  of  alkali  weed.  Only  three 
trees  had  shown  any  increased  growth,  one  of  which.  No.  6,  which  was  in 
.07  per  cent  of  carbonate  of  soda,  had  grown  but  6  inches  in  the  past 
year.     Others  that  had  less  of  the  carbonate  had  died. 

The  crebra  is  certainly  not  suited  to  alkali  conditions. 

EFEECT  0E  ALKALI  ON  EUCALYPTUS  CORNUTA. 

Cormita  was  one  of  the  species  of  eucalypts  chosen  for  the  Tulare 
Station  plot  and  27  young  seedlings  were  set  out  early  in  the  year  and 
given  the  same  irrigation  and  attention  received  by  other  species.  In 
a  good  soil  the  growth  was  as  great  during  the  first  year  as  made  by  any 
other  species  in  this  plot,  the  height  reached  being  48  inches,  but  only 
two  of  the  trees  reached  this.  Five  other  trees  grew  from  36  to  48 
inches,  ten  from  24  to  36  inches,  and  three  from  18  to  24  inches ;  seven 
of  the  trees  had  died  either  soon  after  planting  or  after  reaching  a  foot 
or  more  in  height. 

The  soils  of  only  six  of  the  trees  that  were  apparently  affected  by 
alkali  salts  were  taken  for  examination.  Tree  No.  2  had  been  planted 
in  a  sandy  soil  with  hardpan  at  two  feet  and  was  evidently  killed  by 
lack  of  moisture,  as  the  amount  of  alkali  was  very  small.  No.  4  was 
green  but  the  tips  of  the  leaves  were  beginning  to  turn  yellow ;  its  soil 
was  sandy  to  two  feet  depth  and  underlaid  by  a  clayey  soil.  No.  6  had 
grown  to  a  height  of  two  feet  in  a  soil  having  hardpan  at  four  feet,  but 
had  finally  succumbed  to  the  alkali.  No.  8  in  a  soil  similar  to  that  of 
No.  4  was  more  severely  affected  by  the  alkali,  some  of  the  leaves  begin- 
ning to  die.  No.  10  in  a  soil  with  .5  per  cent  of  alkali  salts  and  with 
a  moist  clayey  subsoil  at  three  feet  showed  signs  of  injury  as  some  of 
the  leaves  were  dying ;  and  No.  12  in  a  soil  similar  to  that  of  No.  10  but 
with  less  total  salts  and  more  carbonate  of  soda  also  showed  the  effect  of 
the  latter  by  the  dying  of  the  lower  leaves. 


264 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


The  results  of  the  examination  are  given  in  the  following  table : 
E.  cornuta  in  Alkali  Soil. 


H 
a 
11 

c 

W 

Condition. 

Percentage  in  soil. 

Pounds  per  acre,  3  feet. 

CO 

s= 

SO 

ST 

CO 

to    ? 

a 

1* 

H 

o 

E 

CO 
9 

P    to 

S3- 

2  ° 

a 

o 

I 

10 

42 
24 
20 
18 
24 

A  few  leaves  dying 

.43 
.09 
.24 
.53 
.26 

.04 
.04 
.07 
.04 
.05 

.02 
.01 
.01 
.06 

.01 

.49 
.14 
.32 
.63 
.32 

51,600 
10,800 
28,800 
60,600 
31,200 

4,800 
4,800 
8,400 
4,800 
6,000 

2,400 
1,200 
1,200 
1,200 
1,200 

58,800 
16,800 

4 

Tips  of  leaves  changing 

1? 

Lower  leaves   dying 

38,400 

8 

Leaves  dying  "__ 

66,600 

6 

Dead    

38,400 

From  this  table  it  would  appear  that  the  cornuta  is  quite  sensitive  to 
the  presence  of  alkali  salts  in  its  soil,  if  the  amount  be  as  much  or  more 
than  .5  per  cent  of  total  salts. 

It  reached  its  maximum  height  of  48  inches  in  .15  per  cent  of  alkali, 
and  42  inches  in  as  much  as  .49  per  cent,  but  in  the  latter  the  leaves 
had  begun  to  die,  evidently  from  the  effect  of  the  alkali.  The  carbonate 
of  soda  seems  to  be  controlling  cause  of  injury  to  the  trees  for  there  was 
but  .01  per  cent  (1,200  pounds  per  acre  3  feet  depth)  where  the  tree 
was  not  affected  and  .04  per  cent  where  the  leaves  were  dying  though 
the  tree  was  42  inches  high.  In  another  spot  a  tree  had  grown  45  inches 
without  apparent  injury  in  presence  of  .17  per  cent  of  total  alkali  and 
.01  per  cent  of  carbonate  of  soda. 

We  would  then  place  the  limits  of  tolerance  on  the  part  of  cornuta 
at  about  .5  per  cent  of  total  alkali  salts,  provided  there  was  not  more  than 
.03  per  cent  of  carbonate  of  soda  present. 

Observations  in  1910. — A  visit  to  the  Tulare  Station  after  its  abandon- 
ment showed  that  all  of  the  twenty  cornuta  trees  were  dead  along  the 
row  through  the  dense  patch  of  weeds  to  the  east  end,  where  a  few  trees 
had  survived  and  had  made  additional  growth  of  a  foot  or  more  in  weak 
alkali  soil.     The  trees  were  killed  by  the  alkali  and  the  alkali  weeds. 

The  cornuta  is  evidently  not  an  alkali-resistant  eucalypt. 


EFFECT  OF  ALKALI  ON  EUCALYPTUS  GLOBULUS. 

There  were  only  twenty-eight  seedlings  of  Eucalyptus  globulus  put 
in  a  row  across  the  alkali  plot  of  the  Tulare  Station,  a  few  being  in  that 
part  which  contained  40,000  to  60,000  pounds  (.35  to  .50  per  cent)  of 
the  salts  in  a  depth  of  3  feet  per  acre.  The  irregular  distribution  of  the 
salts  is  well  shown  in  diagram  No.  1 ;  No.  5  having  a  total  of  .12  per  cent, 
while  No.  6,  six  feet  distant,  has  .35  per  cent,  and  No.  7  at  a  distance 
of  six  feet  from  No.  6  has  more  than  .50  per  cent  of  alkali  in  three  feet 
depth. 


BULLETIN  225]         TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI. 


265 


The  greatest  height  attained  in  one  season  after  planting  was  34 
inches,  by  two  of  the  seedlings,  in  a  soil  having  but  little  alkali.  Six  of 
the  seedlings  grew  to  30  inches ;  seven  24  inches ;  six  to  18  inches,  while 
the  others  fell  below  this  height,  four  dying  completely.  A  few  were 
selected  for  alkali  examination,  the  samples  of  soil  being  taken  to  three 
feet  in  depth. 

The  seedlings  were  set  out  in  the  spring  and  it  is  more  than  likely 
that  at  that  time  the  surface  soil  was  quite  free  from  alkali  because  of 
the  winter  and  spring  rains,  thus  enabling  the  roots  to  secure  a  foothold 
before  the  subsequent  rise  of  alkali  to  the  roots.  In  the  fall,  at  the  time 
the  soil  samples  were  taken  for  examination,  a  detailed  analysis  showed 
that  the  alkali  was  concentrated  in  the  upper  two  feet  where  the  young 
seedling  roots  were  held  subject  to  its  influence.  It  was  also  found 
that  while  the  sulfates  and  the  common  salt  were  each  chiefly  in  the 
upper  two  feet,  the  carbonate  of  soda,  on  the  contrary,  was  mainly 
held  in  the  first  foot.  The  results  of  analysis  are  shown  in  the  following 
table : 

E.  GLOBULUS  IN  ALKALI  SOIL. 


Percentage  in  soil. 


Pounds  per  acre,  3  feet. 


Leaves    touched 
Leaves    touched    . 
Leaves  dying  . 
Leaves  dying-  . 

Dead    

Leaves  turning 
Leaves  dying  . 

Dead    

Dead    

Dead    


.03 
.04 
.07 
.03 
.04 
.05 
.04 
.04 
.04 
.06 


49.200 
34,800 
16,800 
34,800 
55,200 

7,200 
39,600 

6,000 
55,200 
14,400 


3,600 
4.800 
8,400 
3,600 
4,800 
6,000 
4,800 
4,800 
4,800 
7,200 


2,400 
1,200 
2,400 
1,200 
1,200 
1,200 
2,400 
1,200 
1,200 
1,200 


55,200 
40,800 
27,600 
39,600 
61,200 
14,400 
46,800 
12,000 
61,200 
23,800 


A  study  of  the  alkali  figures  and  the  condition  of  the  trees  point 
plainly  to  the  fact  that  it  is  a  mistake  to  base  the  tolerance  of  alkali  by 
a  plant  alone  upon  the  total  amount  present  in  a  certain  depth  of  soil, 
but  that  the  amounts  of  individual  salts  must  be  taken  into  account. 
Thus,  we  find  the  tree  growing  to  its  maximum  height  of  30  inches  in  a 
spot  wThere  there  was  .46  per  cent  of  total  alkali  (55,200  pounds  per 
acre  in  3  feet),  while  it  was  dwarfed  in  much  smaller  amounts  because 
of  the  presence  of  more  carbonate  of  soda  in  the  upper  two  feet.  In 
another  spot  the  growth  was  but  18  inches  in  presence  of  .51  per  cent 
of  alkali,  but  the  tree  had  died,  and  probably  the  slow  growth  as  well  as 
the  death  of  the  seedling  was  due  to  the  larger  amount  of  carbonate  of 
soda  as  well  as  of  the  total  alkali. 

That  the  sulfate  of  soda  has  but  little  injurious  effect  on  any  plant, 
except  in  very  large  amounts,  has  been  shown  in  other  publications  of 


266  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

this  station,  and  is  here  well  illustrated  in  tree  No.  10  which  grew  to  a 
height  of  30  inches  in  the  presence  of  .41  per  cent  of  sulfates,  or  the 
equivalent  of  about  50,000  pounds  per  acre  in  a  depth  of  3  feet. 

The  carbonate  of  soda  was  the  most  hurtful  of  the  alkali  salts,  and 
the  seedlings  seem  to  show  in  their  leaves  that  they  feel  the  effect  of 
.04  per  cent,  though  the  plant  No.  11  reached  its  maximum  growth  of 
30  inches  in  a  soil  containing  that  percentage.  Where  the  percentage 
of  carbonate  of  soda  was  more  than  .04  the  seedlings  were  either  dwarfed 
in  growth  or  dead.  It  seems,  then,  that  the  limit  of  tolerance  of  the 
E.  globulus  for  carbonate  of  soda  may  be  placed  at  .04  per  cent  or  its 
equivalent  of  about  5,000  pounds  per  acre  in  a  depth  of  three  feet. 

The  tree  is  not  as  susceptible  to  common  salt  as  to  carbonate  of  soda, 
and  the  amounts  found  in  the  row  of  trees  are  hardly  worthy  of  con- 
sideration, the  highest  amount  being  but  .02  per  cent,  or  2,400  pounds 
in  3  feet  depth  per  acre,  and  in  this  it  reached  nearly  its  greatest  growth. 

It  is  evident  that  other  causes  than  alkali  alone  have  caused  the 
death  or  dwarfing  of  many  of  the  seedlings.  In  fact,  Nos.  4  and  13, 
which  were  killed,  and  No.  5,  which  was  dwarfed,  were  in  soils  holding 
less  total  salts,  as  well  as  less  of  each  salt  than  No.  12  which  grew  to  a 
height  of  18  inches. 

Observations  in  1910. — Observations  made  a  year  later  on  the  condi- 
tion of  the  young  globulus  at  the  station  showed  that  every  young  tree 
from  Nos.  4  to  20,  had  died  either  from  lack  of  water,  from  the  effect 
of  alkali,  or  because  of  the  dense  mass  of  alkali  weed  that  had  been 
allowed  to  grow  after  the  station  was  abandoned.  All  of  the  plants,  the 
analyses  of  whose  soils  are  given  in  the  tables,  were  dead  and  only  out- 
side of  the  weed  patch  and  almost  wholly  on  the  east,  where  there  was 
but  little  alkali,  had  the  trees  made  additional  growth,  the  maximum 
increase  being  about  four  feet. 

Young  E.  globulus  at  Buena  Park,  Orange  County. — Buena  Park  is 
located  in  the  region  of  alluvial  lands  that  lie  south  of  Los  Angeles.  In 
this  is  a  young  grove  of  E.  globulus  on  the  east  side  of  the  railroad,  two 
miles  north  of  Buena  Park,  which  was  planted  three  years  before  this 
examination  was  made.  A  large  alkali  spot  occurs  in  the  grove,  and 
though  planted  and  treated  as  the  rest,  the  young  trees  within  its  area 
were  killed  by  the  excessive  alkali  which  covers  the  ground  in  summer 
with  a  white  crust.  The  alkali  spot  is  irregular  in  outline  and  along  its 
border  are  trees  that  have  been  more  or  less  dwarfed  by  the  alkali  and 
seemed  to  afford  good  examples  for  study. 

The  accompanying  photographs  show  the  conditions  prevailing  in 
this  field ;  Fig.  3  is  a  view  of  the  thick  crust  of  alkali  salts,  cut  into  by  the 
wheel  of  the  vehicle.  The  soil  had  been  thrown  up  into  ridges  for  irri- 
gation and  the  planting  of  the  eucalypts;  the  tops  of  the  ridges  show 
thicker  alkali  than  in  the  swales  where  it  is  weaker  and  permits  of  the 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali. 


26' 


growth  of  alkali  weeds.  The  trees  that  were  planted  all  died,  except 
along  the  border,  as  shown  in  the  photo,  and  there  those  in  front  were 
lower  in  height  than  those  in  the  rear  though  of  the  same  age,  evidently 
the  effect  of  the  stronger  alkali.  The  other  photograph  is  a  nearer  view 
of  the  tall  trees  with  smaller  ones  on  the  right,  which  in  turn  give  way  to 
only  alkali  weeds  and  grass  and  finally  to  only  alkali  salts,  as  shown 
in  the  other  photograph.  Soils  Nos.  1,  2  and  9  are  from  the  locality 
shown  in  Fig.  4,  while  the  others  are  from  along  the  border  of  the  trees 
shown  in  Fig.  3. 

Certain  of  the  young  trees  were  chosen  that  were  seemingly  affected 
differently  by  different  amounts  of  the  alkali  and  samples  of  their  soil 
were  taken  within  a  few  inches  of  the  tree,  and  to  a  depth  of  4  feet,  and 
submitted  to  chemical  analysis.  The  results  are  shown  in  the  following 
table : 


E.   GLOBULUS   IN    ALKALI   SOIL   NEAR   BUENA   PARK,    LOS   ANGELES    COUNTY. 


M 

o 

— 

o 

a- 

s 

1 

22 

2 

10 

3 

10 

4 

3 

5 

6 

6 

7 

7 

8 

8 

9 

11 

-— 

Percentage  in  soil. 


CO 

'  o 

n    1 

c 

3    So 

g 

p 

£3- 
2  ? 

o 

tn 

a    1 

r  i 

.21 

.02 

.03 

.11 

.04 

.01 

.17 

.02 

.03 

.18 

.02 

.05 

.22 

.06 

.04 

.33 

.05 

.10 

.36 

.02 

.12 

.19 

.05 

.05 

.27 

.09 

.03 

.49 

.02 

.12 

.53 

.12 

.14 

Pounds  per  acre,  4  feet. 


.3    P> 
a>  o 

£    ■ 
ST 

3,200 

4,800 

6,400 

1,600 

3,200 

4,800 

3,200 

8,000 

9,600 

6,400 

8,000 

16,000 

3,200 

19,200 

8,000 

8,000 

14,40d 

4,800 

3,200 

19,200 

19,200 

22,400 

4J  inches  in  diameter. 
11  inches  in  diameter. 
1|  inches  in  diameter- 
Healthy 

Lower   branches   dead 

Dying    

Dead    

Salt  grass  only 

Salt  grass  and  weeds. 

Salt  grass  only 

Nothing  growing 


.26 
.16 
.22 
.25 
.32 
.48 
.50 
.29 
.39 
.73 
.84 


17,600 
27,200 
28,800 
35,200 
52,800 
57,600' 
30,400 
43,200 
78,400 
92,800 


41,600 
25,600 
35,200 
40,000 
51,200 
76,800 
80,000 
46;400 
62,400 
100,800 
134,400 


In  this  grove  we  found  a  tree,  No.  1,  22  feet  in  height  growing  where 
there  was  no  indication  of  alkali,  as  the  ground  around  it  was  covered 
with  grass,  and  yet  the  examination  showed  the  presence  of  .26  per  cent 
(nearly  42,000  pounds  per  acre)  of  total  salts  in  4  feet  depth.  The  tree 
was  in  splendid  condition,  full  foliage  and  with  a  trunk  having  a 
diameter  of  four  and  one  half  inches.  There  was  but  .02  per  cent  of 
carbonate  of  soda  in  the  soil.  A  tree,  No.  2,  near  this,  having  a  height 
of  but  ten  feet,  though  of  the  same  age,  had  twice  the  amount  of  car- 
bonate of  soda,  .04  per  cent  (6,400  pounds  per  acre)  in  four  feet  depth. 
The  tree  was  healthy  and  had  a  diameter  of  one  and  three  fourths  inches. 
The  diminished  growth  is  probably  due  to  the  larger  amount  of  car- 
bonate of  soda,  for  in  a  soil  having  a  still  greater  amount,  .06  per  cent 
(9,600  pounds  per  acre),  a  tree,  No.  5,  was  growing  with  a  height  of  but 
six  feet  and  some  of  the  lower  branches  were  dead.  A  few  feet  from 
No.  2  the  alkali  was  so  strong,  No.  9,  that  only  salt  grass  and  alkali 
weeds  would  grow  in  it.  Where  the  trees  Nos.  6  and  7  were  dead  or  dying 


268  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


Fig.   3. — Alkali  field  with  Eucalyptus  globulus  on  border 


Fig.   4. — Eucalyptus  globulus  on  border  of  alkali  field.      Alkali  weeds  in  foreground. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  269 

the  cause  seemed  to  be  the  great  excess  of  alkali  salts,  which  covered  the 
ground  with  a  white  incrustation  and  prevented  proper  aeration ;  that 
the  common  salt  alone  was  not  responsible  is  shown  by  the  fact  that  tall 
trees  have  been  found  in  other  places  growing  well  in  as  much  as  .50 
per  cent  or  an  equivalent  of  about  40,000  pounds  per  acre  in  two  feet 
depth. 

It  will  be  seen  from  the  table  that  where  there  was  as  much  as  .48  per 
cent  of  alkali  salts,  comprising  very  high  per  cents  of  carbonate  or  com- 
mon salt  the  E.  globulus  was  dying  when  7  feet  high;  and  that  where 
there  was  as  much  as  .09  per  cent  of  carbonate  of  soda  (14,400  pounds 
per  acre),  only  salt  grass  and  alkali  weeds  will  grow;  that  salt  grass 
alone  grew  in  presence  of  .49  per  cent  of  sulfates  and  .12  per  cent  of 
common  salt ;  and  that  nothing  at  all  was  able  to  live  in  .84  per  cent  of 
total  salts  (134,400  pounds  per  acre)  in  which  there  was  .12  per  cent 
of  carbonate  and  .14  per  cent  of  common  salt. 

Groves  of  E.  globulus  in  other  Localities. — A  grove  of  E.  globulus  near 
Centralia  schoolhouse,  a  few  miles  southwest  of  Buena  Park,  was  planted 
in  1909  in  a  strip  of  alkali  land  and  the  trees  showed  varying  effects  of 
the  alkali  salts.  The  grove  was  visited  by  Mr.  F.  E.  Johnson  and  soils 
taken  from  near  a  number  of  the  trees  and  examined.  The  greatest 
height  of  the  unaffected  trees  was  3  feet  and  the  one  of  this  height 
selected  was  growing  in  19,200  pounds  of  salts,  the  greater  part  of  which 
was  sulfates.  Other  trees  more  or  less  affected  are  given  in  the  table 
below. 

In  the  region  around  Fresno  were  found  many  old  trees  growing  in 
alkali  soils,  some  of  which  were  examined  by  Mr.  Johnson;  No.  5, 
about  twenty-five  years  old,  tall  and  having  a  diameter  of  about  15 
inches,  showed  no  indication  of  injury  from  the  alkali;  No.  6,  twenty- 
five  years  old,  thirty-five  feet  tall  and  having  a  diameter  of  12  inches 
was  growing  in  a  locality  whose  soils  seemed  to  be  strongly  charged 
with  alkali  salts  and  underlaid  at  a  depth  of  about  3  feet  by  hardpan. 
It  was,  however,  but  slightly  affected  by  the  alkali  although  there  was  a 
large  (.05  per  cent)  amount  of  carbonate  of  soda.  No.  7,  eight  years 
old,  was  severely  affected  by  the  strong  alkali  about  its  roots,  was  sickly 
in  appearance  and  many  of  its  leaves  were  reddish  in  color ;  and  No.  8, 
six  }Tears  old,  growing  in  a  soil  having  .14  per  cent  (22,400  pounds  per 
acre  4  feet)  of  carbonate  of  soda  was  stunted  in  growth  though  other- 
wise showing  no  effects  of  the  alkali.  This  is  the  largest  amount  of 
carbonate  of  soda  found  in  the  soil  of  any  eucalypt  (except  an  unidenti- 
fied species)  that  had  attained  any  considerable  growth.  Unfortunately, 
the  early  treatment  of  the  tree  is  not  known,  but  it  was  doubtless  well 
cared  for  and  the  alkali  kept  from  the  young  roots  until  they  had  passed 
beyond  the  danger  zone. 


270 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


The  results  of  the  soil  examination  are  given  in  the  following  tabh 

E.   GLOBULUS   IN    ALKALI    SOILS. 


s 

B 

z 

p 

p 

CO 

2 

Effdct  of  alkali. 


1 

36  in. 

1 

30  in. 

1 

24  in. 

1 

14  in. 

25 

Tall 

25 

35  ft. 

8 

6 



Centralia  Schoolhouse 

None   

Slight   

Moderate    

Severe  

Near  Fresno. 

None   

Slight   

Sickly   

Stunted   


Percentage  in  soil. 


S-  c       o 


Pounds  per  acre.  4  feet. 


p "  o 


12,800 
22,400 
24,000 
32,000 


80,000 
3,200 
12,800 
17,600 


3,200 
1,600 
1,600 
8,000 


8,000 

8,000 

11,200 

22,400 


3,200 
4,800 
3,200 
8,000 


4,800 
8,000 
6,400 
4,800 


19,200 
28,800 
28,800 
48,000 


92,800 
19,200 
30,400 
44,800 


In  the  above  table  there  is  seen  to  be  a  regular  gradation  in  height 
of  the  young  trees  near  Centralia  schoolhouse  from  30  inches  to  14 
inches  following  the  increasing  amounts  of  alkali  salts  from  .12  to  .30 
per  cent  (19,000  to  48,000  pounds  per  acre)  in  4  feet  depth,  and  the 
conclusion  is  inevitable  that  this  increase  has  something  to  do  with  the 
dwarfing  or  retarding  of  the  growth.  It  is  clear  that  .02  per  cent  of 
carbonate  of  soda  in  4  feet  depth  per  acre  has  no  effect  on  the  young 
tree,  while  it  would  seem  that  the  tree  does  severely  feel  the  presence  of 
a  little  more  than  twice  that  amount. 

When,  however,  we  turn  to  the  older  trees  from  near  Fresno,  we  find 
that  they  are  not  at  all  affected  by  these  amounts,  and  are  growing  well 
in  as  much  as  .07  per  cent  (11,200  pounds  per  acre)  each  of  the  car- 
bonate and  chlorid  in  four  feet  depth,  though  stunted  in  the  presence 
of  .14  per  cent  of  carbonate  of  soda.  Evidently  the  delicate  roots  have 
managed  to  escape  contact  with  this  large  amount  of  carbonate  of  soda, 
and  had  passed  beyond  the  danger  point  before  the  alkali  returned  to 
the  surface.  The  sulfates  even  to  the  extent  of  .5  per  cent  or  80,000 
pounds  per  acre  4  feet  depth  also  seem  not  to  be  hurtful  to  the  tree. 

This  table  is  very  instructive  and  from  it  we  must  conclude  that  the 
tender  bark  of  the  roots  of  the  globulus  when  very  young  are  very  sus- 
ceptible to  corrosion  and  injury  by  as  much  as  .05  per  cent  or  8,000 
pounds  of  carbonate  of  soda  in  four  feet  depth ;  but  if,  by  irrigation,  the 
alkali  can  be  carried  down  to  several  feet  below  the  surface  and  kept 
there  by  proper  cultivation  and  mulching  of  the  surface  soil  until  the 
tree  is  able  to  send  the  roots  deeply  and  far  out  laterally  beyond  the 
alkali,  and  has  time  to  envelope  the  surface  roots  with  a  thick  bark  not 
susceptible  to  the  alkali,  there  may  be  present  double  the  amount  of 
alkali  without  injury  to  the  tree. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali. 


271 


The  accompanying  photograph  Fig.  5  is  of  a  globulus,  75  feet  high, 
growing  in  an  alkali  soil  west  of  Wasco,  Kern  County.  When  young, 
the  tree  had  had  thorough  irrigation  from  an  artesian  well  on  the  place 
which  had  carried  the  greater  part  of  the  alkali  salts  to  a  depth  below 
five  feet,  as  was  shown  by  an  examination  of  a  seven-foot  column  of  the 


Fig.   5. — Eucalyptus   globulus   in   alkali    soil.      Effect   of 
irrigation. 

soil  taken  a  few  years  ago ;  at  that  time  there  was  .05  per  cent  of  alkali 
in  the  upper  four  feet  and  .14  per  cent  in  the  lower  three  feet.  The 
sulfates  and  chlorid  were  chiefly  in  the  lower  part  of  the  column  while 
the  carbonate  of  soda  was  about  evenly  distributed  throughout. 


272 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


E.  globulus  in  Salt  Marshes  and  Tide  Islands. — The  swamp  and  tule 
lands,  that  mark  the  junction  of  the  two  great  rivers  of  the  Sacramento 
and  San  Joaquin  lying  in  the  great  valley  and  covering  approximately 
1.000  square  miles,  are  largely  at  or  near  tide  water  or  sea  level,  and 
intersected  irregularly  by  sloughs  which  divide  the  region  into  many 
"islands,"  whose  lands  have  to  be  protected  against  overflow  from  the 
rivers  by  levees  before  being  capable  of  safe  cultivation  and  crop  produc- 
tion. The  water  of  these  sloughs,  as  well  as  of  the  rivers  for  many  miles 
upstream,  are  more  or  less  mixed  with  the  salty  tide  water  of  the  bay, 
and  by  percolation  the  salt  has  been  carried  into  the  lands  of  the  islands, 
as  well  as  rising  into  the  levees  that  surround  them. 

Along  the  levees  of  a  number  of  these  islands  there  were  planted 
many  years  ago  long  rows  of  eucalypts,  mostly  of  the  globulus  variety, 
to  serve  as  windbreaks.  These  trees  have  grown  to  heights  of  from  40 
to  60  or  more  feet  although  some  of  their  roots  are  bathed  constantly  by 
salt  water,  and  others  are  living  in  a  soil  of  but  two  or  three  feet  above 
water  level  and  carrying  a  high  percentage  of  salts. 

Similarly,  the  salt  marshes  that  border  the  bay  of  San  Francisco  in 
Marin  County,  known  as  the  Novato  Meadows,  have  many  trees  growing 
in  the  shallow  and  more  or  less  salty  soil. 

Samples  of  soil  from  very  near  some  of  these  trees  of  the  Novato 
Meadows,  and  from  one  of  the  ' '  islands ' '  were  taken  down  to  the  water 
level  (two  feet),  and  subjected  to  analysis  with  the  following  results: 

E.   GLOBULUS  IN   ALKALI   SOILS  OF  MARSH  AND  TULE  LANDS. 


Percentages. 

Pounds  per  acre,  2  feet. 

Sulfates. 

Chlorids. 

Total. 

Sulfates. 

Chlorids. 

Total. 

Tule  Island  _    __    

.69 
.14 

.56 
.42 

1.25 
.56 

1 

55,000 
11,200 

44,800 
33,600 

99,800 

Novato  Meadows 

44,800 

These  are  very  large  amounts  of  each  salt  and  plainly  show  that  the 
globulus  is  not  sensitive  to  the  presence  of  either  sulfate  of  soda  or  com- 
mon salt  in  its  soils.     There  was  no  carbonate  of  soda  in  soils  examined. 

We  find,  then,  that  Eucalyptus  globulus,  after  passing  the  young  stage 
of  growth  and  getting  its  roots  deeply  in  the  soil,  will  withstand  a  large 
amount  of  alkali  salts,  provided  the  carbonate  of  soda  does  not  exceed 
.05  per  cent. 


EFFECT  OF  ALKALI  ON  E.  RUDIS. 

In  the  alkali  plot  of  the  Tulare  Experiment  Station  there  were  planted 
25  young  seedlings  of  E.  rudis,  eight  of  which  reached  a  maximum 
height  of  36  inches  during  the  first  season  after  planting  both  in  a  soil 
having  but  little  alkali  and  in  the  spot  having  as  much  as  .14  per  cent  or 


BULLETIN  225]         TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI. 


273 


nearly  17,000  pounds  per  acre  in  3  feet  depth,  of  which  nearly  one  half 
was  carbonate  of  soda.  Twelve  others  of  the  seedlings  grew  from  24 
inches  to  36  inches,  and  the  others  from  15  to  24  inches.  None  of  the 
young  trees  were  killed  by  the  alkali,  though  some  were  dwarfed  and 
failed  to  reach  the  height  they  should  have  done. 

E.  rudis  in  Alkali  Soils  :  Tulare  Station. 


Percentage  in  soil. 


Pounds  per  acre,  3  feet. 


c 

o 

so    J* 

6,000 

9,600 

1,200 

31,200 

6,000 

2,400 

25,200 

8,400 

2,400 

28,800 

7,200 

2,400 

42,000 

6,000 

1,200 

19,200 

6,000 

3,600 

20,400 

8,400 

1,200 

Good   

Leaves  affected 

Good  

Good   

Good  

Good  

Good  


.05 


16,800 
40,600 
36,000 
38,400 
49,200 
28,800 
28,000 


Unfortunately  for  the  experiment,  the  row  of  young  seedlings  did  not 
cross  the  part  of  the  plot  having  the  strongest  alkali,  and  hence  were  not 
subjected  to  as  severe  a  test  as  the  cornuta  and  globulus,  where  the 
maximum  amount  of  alkali  salts  was  .51  per  cent  or  about  61,000  pounds 
per  acre  in  3  feet  depth. 

The  maximum  amount  of  total  salts  in  the  rudis  test  was  .41  per  cent 
or  about  49,200  pounds  per  acre,  and  in  this  the  seedling  reached  a 
height  of  18  inches.  The  lowest  height  of  any  tree  was  15  inches  and 
this  was  in  the  presence  of  only  .25  per  cent  or  28,000  pounds  per 
acre,  but  in  this  there  was  .07  per  cent  (8,000  pounds  per  acre)  of  car- 
bonate of  soda.  That  other  conditions  than  alkali  alone  had  affected  the 
rudis  was  shown  in  seedlings  Nos.  7  and  14,  each  with  a  height  of  18 
inches  and  in  whose  soils  there  was  respectively  .41  and  .24  per  cent 
of  alkali,  and  in  which  the  carbonate  and  the  chlorid  were  almost  the 
same  in  amount.  In  other  places  also  where  there  was  but  little  alkali 
the  growth  was  very  small. 

Conditions  in  1910. — Observations  made  on  the  rudis,  a  year  later 
than  above  and  after  the  station  had  been  abandoned  leaving  the  plot 
entirely  neglected,  showed  that  eleven  of  the  young  trees  had  died, 
comprising  those  in  the  center  of  the  row  and  where  a  dense  and  tall 
growth  of  alkali  weed  had  appeared.  However,  seven  of  the  trees  in 
this  weed  patch  had  increased  from  24  to  36  inches  in  height  and  two 
more  were  holding  their  own  and  were  the  only  eucalypts  living  within 
this  area,  with  the  exception  of  one  each  of  tereticornis  and  crebra 
which  were  in  the  edges  of  the  weeds.  The  killing  out  of  the  trees  was 
due  doubtless  to  the  lack  of  water  and  to  the  presence  of  the  weeds,  as 


274  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 

the  amount  of  carbonate  of  soda  present  in  their  soils  was  less  than  in 
No.  5,  #  which  still  lived  in  .08  per  cent. 

Other  Localities. — In  the  investigations  made  by  Mr.  Johnson  in  other 
parts  of  the  State,  samples  of  alkali  soil  were  taken  from  twenty-five  or 
more  of  the  E.  rudis  and  submitted  to  analysis.  The  greater  number 
of  these  had  less  alkali  than  could  produce  unfavorable  effects  upon  the 
tree  and  all  but  nine  have  been  omitted  from  the  table. 

The  first  tree  given  in  the  following  table  was  from  near  Fresno ;  it 
was  three  years  old,  8  feet  high,  and  well  proportioned  and  showed  no 
bad  effect  of  the  .20  per  cent  of  alkali  in  its  soil.  No.  2  from  Kingsburg 
also  was  in  good  health,  though  growing  in  a  soil  with  .25  per  cent  of 
alkali  salts,  and  had  received  no  cultivation.  No.  3  from  Hanford, 
5  feet  high,  had  received  fairly  good  cultivation  and  was  not  suffering 
from  the  .28  per  cent  of  alkali  in  its  soil,  which  was  equal  to  nearly 
50,000  pounds  per  acre  in  4  feet  depth.  A  detailed  analysis  of  each 
foot  showed  that  the  carbonate  of  soda  was  distributed  rather  evenly 
through  the  four-foot  column,  that  three  fifths  of  the  sulfates  and  of  the 
chlorids  also  were  in  the  first  foot  and  one  fifth  in  the  second  foot.  The 
water  level  was  at  five  feet.  No.  4  from  Kingsburg  had  received  no 
cultivation  and  was  growing  in  hard  ground  covered  with  weeds  and  salt 
grass.  A  gravelly  hardpan  occurred  at  two  feet  below  the  surface  but 
the  roots  of  the  tree  had  passed  through  it  into  the  soil  below.  Notwith- 
standing these  drawbacks  and  the  presence  of  .24  per  cent  of  alkali  salts, 
the  tree  was  not  suffering.  No.  5  from  Hanford,  three  years  old  and  15 
feet  high,  was  growing  in  a  soil  covered  with  a  powdery  coating  of  alkali 
and  holding  .20  per  cent  of  alkali.  Grapes  had  all  died  in  this  soil,  but 
the  rudis  showed  no  marked  ill  effect  except  in  smaller  leaves  and  red 
spots.  No.  6  from  the  same  place  had  been  planted  in  a  barrel  filled 
with  good  soil  and  covered  over  with  manure  and  sunk  into  the  alkali- 
crusted  soil;  the  seedling  reached  a  height  of  6  feet  in  two  years,  but 
the  alkali  became  diffused  into  the  soil  of  the  barrel  and  the  tree  began 
to  show  some  bad  effects.  No.  7  from  Fresno  had  apparently  died  down 
and  again  grown  up  from  a  sucker ;  it  looked  very  badly  though  5  feet 
high,  many  of  the  tips  of  the  shoots  being  dead  and  some  of  the  leaves 
mottled  red,  though  the  amount  of  alkali  was  not  large.  No  8  from 
near  Fresno  was  6  feet  tall,  with  but  few  branches  and  some  of  the 
leaves  near  the  ends  of  the  branches  being  mottled  red.  No.  9  from 
Hanford,  one  year  old  standing  in  strong  alkali  soil,  crusted  over  with 
alkali  was  alive  but  not  growing. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali. 


275 


E.  rudis  in  Alkali  Soils. 


Percentage  in  soil. 


Pounds  per  acre,  4  feet. 


Locality. 


Effect  of  alkali. 


& 

a 

c 

3  & 

p 

a  o 

■Jl 

: 

.09 

.05 

.13 

.04 

.16 

.07 

.13 

.04 

.14 

.05 

.04 

.08 

.05 

.04 

.09 

.07 

.04 

.09 

03 

Q 

a 

3    S» 

3  ? 

a 

V 

o 

14,400 

8,000 

9,600 

20,800 

6,400 

12,800 

25,600 

11,200 

8,1)00 

20,800 

6,400 

11, 2(H) 

22,400 

8,000 

1,600 

6,400 

12,800 

1 ,600 

8,000 

6,400 

4,800 

14,400 

11,200 

9,600 

6,400 

14,400 

1,600 

Fresno 

Kingsburg. 
Hanford  — 
Kingsburg. 
Hanford  _. 
Hanford  .. 

Fresno 

Fresno 

Hanford  _. 


No  effect  _ __ 

No  efYect 

No  effect ._ 

No   bad  effect 

Leaves  spotted  red 
Leaves  spotted  red 
Mottled  red  leaves. 
Mottled  red  leaves. 
Alive,  but  not 
growing    


.01 


32,001) 
40,000 
49,800 
38,400 
32,000 
10,800 
19,200 
35,200 

22,400 


There  is  not  much  to  be  said  regarding  these  results,  except  that  the 
rudis  was  not  affected  by  as  much  as  .28  per  cent  or  45,000  pounds  of 
total  alkali  salts  per  acre  in  a  depth  of  4  feet,  even  when  .07  per  cent 
or  11,200  pounds  of  that  was  carbonate  of  soda  and  .05  per  cent  or 
8,000  pounds  was  of  common  salt.  We  find,  however,  that  when  this 
amount  of  carbonate  is  increased  to  nearly  .09  per  cent  or  15,000  pounds 
as  at  Hanford,  the  tree  failed  to  grow  though  keeping  alive. 

Several  of  the  trees  with  less  amounts  of  carbonate  of  soda  had  leaves 
on  some  of  the  branches  that  were  mottled  with  red  spots.  These  spots 
have  been  regarded  as  the  effect  of  the  alkali,  but  this  is  doubtful,  as  we 
find  in  the  Tulare  experiments  that  very  young  trees,  less  than  a  year 
old,  were  not  thus  affected  even  in  9,000  pounds  of  carbonate  of  soda.  A 
height  of  6  feet  in  two  years  is  very  good  for  the  rudis  and  even  if  the 
mottled  leaves  are  thus  colored  by  alkali  the  growth  does  not  seem  to 
be  injured. 

On  comparing  these  with  the  results  of  the  special  test  on  the  alkali 
spot  at  Tulare  Station  given  above,  we  find  that  the  figures  of  tolerance 
in  the  latter  are  higher. 

The  E.  rudis  will  evidently  grow  well  in  a  soil  containing  as  much 
as  .08  per  cent  of  carbonate  of  soda,  if  other  conditions  are  favorable. 


3— BUL  22: 


276 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


EPfECT  OP  ALKALI  SALTS  UPON  t  TERETICORNIS. 

The  only  observations  made  upon  this  species  of  Eucalyptus  were  those 
of  the  special  plot  of  the  Tulare  Station.  In  this  plot  there  were  planted 
thirty-one  young  seedlings  of  the  E.  tereticornis  in  two  rows,  but  not 
across  the  strongest  alkali,  as  will  be  seen  from  the  chart.  It  was  per- 
haps unfortunate  that  the  test  could  not  have  made  more  severe  along 
with  the  globulus,  rudis,  etc.,  for  the  tereticornis  is  regarded  by  some 
as  being  one  of  the  best  alkali-resistant  eucalypts ;  this  is,  however,  not 
borne  out  by  the  Tulare  tests,  for  in  the  entire  number  of  young  trees 
there  were  but  three  that  reached  the  height  of  from  36  to  48  inches 
without  showing  some  sign  of  distress,  as  shown  either  in  the  small 
growth,  or  in  the  yellowing  of  the  leaves,  or  in  tipping  them  with  red.  a 
condition  which  seems  to  come  from  the  alkali.  Twelve  of  the  thirty-one 
seedlings  (38.7  per  cent)  died  completely,  while  others  had  nearly  suc- 
cumbed at  the  end  of  the  first  year.  Twelve  were  from  12  to  24  inches 
high  and  two  not  more  than  10  inches.  Twelve  of  the  young  trees  were 
selected  for  the  examination  of  the  alkali  content  of  their  soil  and 
samples  of  the  latter  were  taken  to  depths  of  3  feet.  The  results  of  the 
analyses  are  given  in  the  following  table,  which  is  arranged  from  highest 
to  lowest  of  tree  growths : 

E.   TERETICORNIS   IN    ALKALI    SOILS  '.   TULARE    STATION. 


Condition  of  tree. 


Well  branched,  trunk  1  in.  diameter 

Two  lower  limbs   affected 

Few  leaves  dying 

Few  lower  leaves  dying 

Leaves  spotted  red 

Yellow    leaves,    spotted    red,    some 

dead   

Small  leaves,  spotted  red 

Nearly   dead   

Dead    

Dead    

Dead    

Dead    


Percentage  In  soil. 


Pounds  per  acre,  3  feet. 


CO 

e 

a 

P    3 

a 

o 

f 

.09 

.01 

.oil 

.18 

.04 

.02 

.06 

.07 

.01   I 

.06 

.05 

.01 

.13 

.07 

.01 

.05 

.05 

.01 

.12 

.05 

.01  : 

.08 

.05 

.01 

.07 

.07 

.01 

.13 

.08 

.02 

.17 

.07 

.01 

.22 

.06 

.01 

o 
S3- 

n>  o 


.14 

10,800 

4,800 

1,200 

.24 

21,600 

4,800 

2,400 

.14 

7,200 

8,400 

1,200 

.12 

7,200 

6,000 

1,200      . 

.21 

15,600 

8,400 

1,200 

.11 

6,000 

6,000 

1,200 

.18 

14,000 

6,000 

1,200 

.14 

9,600 

6,000 

1,200 

.15 

8,400 

8,400 

1,200 

.23 

15,600 

9,600 

2,400 

.25 

18,400 

8,400 

1,200 

.32 

26,400 

7,200 

4,800 

16,800 
28,800 
16,800 
14,400 
25,200 

13,200 
21,200 
16,8(30 
18,000 
27,600 
28,000 
38,400 


The  maximum  of  total  salts  was  .32  per  cent  or  an  average  of  38,400 
pounds  per  acre  in  3  feet  depth ;  that  of  carbonate  of  soda  was  .08  per 
cent  or  9,600  pounds  per  acre,  and  that  of  the  chlorid  or  common  salt 
was  .04  per  cent  or  4,800  pounds  per  acre  in  3  feet  depth.  In  the 
presence  of  each  of  these  amounts  the  young  tree  had  died,  and  was 
nearly  dead  in  smaller  amounts. 

The  alkali  sulfates  are  seen  in  the  above  table  to  have  had  very  little 


BULLETIN  225]        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI.  277 

effect  on  the  young  trees ;  and  the  common  salt  was  not  in  excess  in  the 
soil  of  any  of  the  trees. 

The  carbonate  of  soda  appears  to  be  the  sole  cause  of  injury  from 
alkali,  and  we  find  that  when  the  amount  was  in  excess  of  .04  per  cent 
or  4,800  pounds  per  acre  in  3  feet  depth  the  leaves  began  to  die  or  turn 
yellow,  while  in  larger  amounts  than  .07  per  cent  or  8,400  pounds  per 
acre  the  seedlings  succumbed. 

The  maximum  growth  of  48  inches  was  reached  in  the  presence  of  .03 
per  cent  or  3,600  pounds  of  carbonate  of  soda  in  a  total  of  only  .16  per 
cent  or  about  19,000  pounds  per  acre. 

The  above  is  a  poor  showing  for  the  tereticornis  and  indicates  that  the 
tree  will  not  attain  a  good  growth  if  as  much  as  .05  per  cent  of  carbonate 
of  soda  be  allowed  to  remain  in  the  upper  three  feet  of  soil. 

Observations  in  1910. — The  abandonment  of  the  station  in  1910 
caused  the  alkali  plot  to  be  neglected  and  the  trees  sorely  tested  not  only 
by  lack  of  irrigation  and  by  the  alkali,  but  by  the  dense  growth  of  alkali 
weeds  that  sprang  up  in  the  central  part  of  the  plot  occupied  by  101 
eucalypts.  The  tereticornis  suffered  with  the  rest  and  all  of  the  12 
trees  of  the  two  rows  in  the  weed  patch  that  had  escaped  the  first  effects 
of  alkali  succumbed,  with  the  exception  of  one  on  the  extreme  west, 
which  made  an  additional  growth  of  8  feet  in  presence  of  .04  per  cent 
of  carbonate  of  soda  in  its  soil.  Outside  of  this  patch  two  trees  made 
increased  growths  of  several  feet  but  all  others  died. 

It  may  be  safely  assumed  that  the  tereticornis  will  attain  good  growth 
in  an  alkali  that  does  not  contain  more  than  .04  per  cent  of  carbonate 
of  soda  in  a  depth  of  three  or  four  feet. 


EFFECT  OF  ALKALI  ON  E.  R0STRATA. 

Young  rostrata  seedlings  were  planted  in  the  special  alkali  plot  of  the 
Tulare  Station,  but  unfortunately  not  through  the  strongest  part,  the 
maximum  of  alkali  in  the  two  rows  being  but  .24  per  cent  or  28,800 
pounds  per  acre  in  3  feet  depth.  The  amount  of  carbonate  of  soda  in 
a  portion  of  the  rows  was,  however,  quite  high. 

The  number  of  seedlings  planted  was  54  and  all  but  three  of  these 
remained  alive  at  the  end  of  the  first  season,  though  many  were  greatly 
retarded  in  growth.  The  maximum  height  at  the  end  of  the  first  year 
was  48  inches  in  a  good  soil  which  had  as  much  as  .05  per  cent  or  6,000 
pounds  of  carbonate  of  soda  per  acre  in  3  feet  depth.  But  two  of  the 
seedlings  reached  this  height,  ten  were  36  inches,  seventeen  were  24 
inches  and  twenty-two  were  12  inches  high. 

Soils  three  feet  deep  from  a  number  of  the  typical  trees  were  exam- 


278 


UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 


ined  as  to  alkali  contents  and  the  results  are  given  in  the  following 
table : 

E.   ROSTRATA  IN   ALKALI   SOIL  :   TULARE   EXPERIMENT   STATION. 


8s    46 


13 

36 

LOS 

30 

3 

2  + 

5s 

24 

4 

20 

Gs 

18 

12 

18 

34 

12 

33 

12 

6 

12 

15 

14 

7 

10 



Condition  of  tree. 


Good;  long  branches 

Good;  long  branches 

Good;  long  branches 

Good  

Good  

Slim,  lowest  leaves  affected 

Healthy,  except  few  bottom  leaves 
Short  limbs,  leaves  have  die-back__ 

Healthy,  except  lower  leaves 

Healthy,  except  three  lower  leaves- 
Dying,  some  leaves  dead 

Leaves   slightly   yellow 

Leaves   tipped   dark 

Tree  healthy  

Dead    _ 

Dead    


Percentage  in  soil. 

73 

C 

K 

to 

5 
s 

.07 

a 

o 
a 

► 

.05 

.01 

J 

.09 

.04 

.01 

.] 

.06 

.07 

.01 

J 

.13 

.03 

.01 

J 

.18 

.01 

.02 

.5 

.05 

.05 

.01 

J 

.11 

.03 

.01 

J 

.06 

.06 

.01 

J 

.16 

.05 

.02 

.5 

.10 

.06 

.01 

.1 

.19 

.03 

.02 

.5 

.07 

.07 

.01 

.] 

.12 

.02 

.02 

.] 

.10 

.03 

.01 

J 

.08 

.07 

.01 

J 

.05 

.07 

.01 

.] 

Pounds  per  acre.  3  feet. 


g 

p 

S 

in 

Carbo- 
nates  

2 

o 

8,400 

6,000 

1,200 

10,800 

4,800 

1,200 

7,200 

8,400 

1,200 

15,600 

3,600 

1,200 

21,600 

1,200 

2,400 

6,000 

6,000 

1,200 

13,200 

3,600 

1,200 

7,200 

7,200 

1,200 

19,200 

6,000 

2,400 

12,000 

7,200 

1,200 

22,800 

3,600 

3,200 

8,400 

8,400 

1,200 

14,400 

2,400 

2,400 

12,000 

3,600 

1,200 

9,600 

8,400 

1,200 

6,000 

8,400 

1,200 

1 

15,600 
16,800 
16,800 
20,400 
25,400 
13,200 
18,000 
15,600 
27,600 
20,400 
28,800 
18,000 
19,200 
16,800 
19,200 
15,600 


The  rostrata  reached  its  greatest  height  of  48  inches  in  presence  of 
.05  per  cent  of  carbonate  of  soda,  and  36  inches  in  presence  of  .07  per 
cent — thus  nearly  equalling  the  rudis.  There  is  not  much  to  be  said 
regarding  other  results,  as  the  failure  to  do  well  on  the  part  of  any 
one  of  the  young  seedlings  can  not  be  attributed  to  any  particular  salt 
so  far  as  we  can  determine  unless  it  be  carbonate  of  soda.  The  highest 
amount  of  total  alkali  in  3  feet  depth  in  the  two  rows  of  seedlings  was 
but  .28  per  cent  or  about  29,000  pounds  per  acre,  and  this  was  in  a  small 
spot  in  the*extreme  east  end  of  the  row  where  a  few  had  been  planted; 
the  alkali  here  formed  a  loose  covering  on  the  ground  and  one  of  the 
trees,  No.  34,  was  dying,  seemingly  from  its  effects  combined  with  the 
.03  per  cent  of  carbonate.  In  another  place  where  there  was  a  less 
amount  of  total  alkali,  but  more  of  carbonate  of  soda,  the  tree  (No.  6  s) 
was  but  18  inches  high  and  the  lower  leaves  were  dying.  Other  trees, 
where  the  amount  of  total  salts  was  rather  small  but  the  carbonate  of 
soda  high,  were  dead,  thus  indicating  that  the  carbonate  of  soda  was 
responsible  for  the  injury. 

Where  the  total  salts  are  less  than  .24  per  cent  we  find  that  the  seed- 
ling was  not  affected  by  as  much  as  .05  per  cent  of  the  carbonate  of  soda  ; 
but  that  when  the  carbonate  is  increased  to  .07  per  cent  (8,400  pounds 
per  acre  in  3  feet  depth)  the  leaves  turned  yellow.  The  common  salt 
may  have  had  something  to  do  with  the  injurious  effect,  but  the  amount 
necessary  for  this  does  not  appear  in  the  table. 

Observations  in  1910. — Observations  made  on  the  Eucalyptus  plot  in 
the  Tulare  Station  after  the  latter  had  been  abandoned  showed  that  all 


Bulletin  225]        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI. 


279 


of  the  first  twelve  trees  of  the  north  row  had  been  killed,  either  by  lack 
of  water  or  by  the  dense  mass  of  alkali  weeds  that  had  sprung  up  over 
the  central  part  of  the  plot ;  the  five  trees  of  the  south  row  included  in 
this  wreed  patch  were  also  killed.  All  the  living  trees,  on  the  outside 
of  the  patch  and  chiefly  on  the  east  where  the  weeds  apparently  could 
not  grow,  had  made  increased  growth  of  several  feet.  Tree  No.  15  had 
grown  to  24  inches  and  No.  13  to  8  feet.  In  the  soil  of  both  of  these 
trees  there  was  but  .03  per  cent  of  carbonate  of  soda.  On  the  west  end 
of  the  south  row,  two  of  the  trees  outside  of  the  weed  patch  were  each 
10  feet  high,  which  was  an  increased  growth  of  6  feet  in  a  soil  containing 


Fig.   6. — Eucalyptus  rostrata  in  alkali  soil  ;  Miramonte,  Kern  County. 

.05  per  cent  of  carbonate  of  soda  and  which  had  received  no  irrigation 
during  the  summer. 

Other  Localities. — Trees  of  E.  rostrata  in  other  parts  of  the  State 
were  found  apparently  growing  well  in  strong  alkali  salts  and  samples 
of  their  soils  were  taken  for  examination.  Near  Miramonte,  Kern 
County,  a  group  of  trees  six  years  old  had  a  height  of  about  30  feet; 
when  young  they  had  been  irrigated,  but  of  late  years  have  been 
entirely  neglected  and  were  surrounded  with  salt  grass  and  alkali  weeds. 
In  this  soil  there  was  but  little  carbonate  of  soda,  while  the  amounts 
of  sulfate  of  soda  and  common  salt  were  extremely  large,  the  total 
being  .80  per  cent  or  128,000  pounds  per  acre  in  4  feet  depth.  Tree 
No.  2  was  obtained  near  Fresno,  four  years  old  and  showing  no  effect 
of  the  alkali  salts.     Nos.  3  and  4  are  from  Centralia  schoolhouse  near 


280 


UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 


Buena  Park,  Orange  County,  each  a  year  old ;  one  showing  no  effect  and 
the  other  but  little  effect  of  the  salts  and  each  having  about  the  same 
height.  No.  5  from  Buena  Park,  two  years  old  and  7  feet  high,  in  a 
soil  having  an  enormous  amount  of  alkali,  but  composed  chiefly  of 
sulfate  of  soda  and  common  salt,  showed  but  little  injury.  No.  6,  from 
Visalia,  three  years  old,  6  feet  high,  was  surrounded  by  a  crust  of  alkali 
two  to  three  inches  deep,  the  effect  being  seen  in  the  straggling  branches 
of  the  tree.  Nos.  7  and  8,  from  Centralia,  each  a  year  old  and  two  feet 
high,  showed  somewhat  the  effect  of  the  alkali,  the  latter  tree  having 
some  dead  leaves.  No.  9,  from  near  Bakersfield,  one  year  old,  was  suf- 
fering, but  it  was  thought  would  live.  No.  10  grew  in  the  middle  of  a 
strip  of  alkali  and  was  small  and  stunted.  Nos.  11  and  12  were  barely 
alive. 

E.  ROSTRATA  IN  ALKALI  SOILS. 


i 

Locality. 

CD 

•1 
03 

c 

2. 

Effect. 

Percentage  in  soil. 

Pounds  per  acre,  4  feet. 

p 

CO 

f 

a 

p  & 
S3- 
S  ? 

p 
o 

Si 

en 

o 

c 

i   r 

1-3-           1 

H 
o 

B9 

i 

Miramonte. 

Fresno 

Centralia  _ 

6 
4 
1 
1 
2 
3 
1 
1 
1 
1 
1 
1 

30  ft. 

None 

.70 
.09 
.10 
.11 
1.48 
.02 
.13 
.14 
.15 
.17 
.89 
.34 

.01 
.04 
.03 
.05 
.01 
.08 
.05 
.03 
.01 
.04 
.02 
.06 

.09 
.01 
.02 
.02 
.22 
.01 
.03 
.02 
.17 
.02 
.12 
.12 

.80 
.14 
.15 
.18 

112,000 
14,400 
16,000 
17.600 

1,600 
6,400 
4,800 
8,000 
1,600 
12,800 
8,000 
4,800 
1,600 
6,400 
3,200 
9,600 

14,400 
1,600 
3,200 
3,200 

35,200 
1,600 
4,800 
3,200 

27,200 
3,200 

19,200 

19,200 

128,000 

? 

None  

None 

23,400 

3 

2i  ft. 

3  ft. 
7  ft. 
6  ft. 
2  ft. 
2  ft. 

24,000 

4     Centralia 

Some    

28,800 

5     Buena  Park 

Some    

1.71    236,800 
.11       3.200 

273,600 

6     Visalia 

Some    

17,600 

7     Centralia 

Some    

.21 
.19 
.33 
.23 
1.03 
.52 

20,800 
22,400 
24,000 
27,200 
142,400 
54,400 

33,600 

8     Centralia 

Some 

30,400 

52,800 

10  Centralia  __ 

11  Rio  Bravo  _ 

18  in. 

Stunted  

Barely   alive 

41,800 
164,800 

12      Rio  Bravo 

83,200 

These  results  appear  very  contradictory  in  regard  to  the  amount  of 
the  several  salts  tolerated  by  the  rostrata,  and  we  are  obliged  to  con- 
clude that  other  causes  have  combined  with  the  alkali  to  injure  some  of 
the  trees.  Some  of  the  results  are  remarkable  and  show  that  under 
proper  conditions  or  treatment  the  tree  may  be  enabled  to  withstand 
the  effect  of  very  high  percentages  of  each  of  the  several  salts  com- 
prising the  alkali.  Thus,  we  find  that  a  two-year-old  tree  at  Buena 
Park  has  reached  the  height  of  7  feet  and  has  suffered  but  little  in  the 
presence  of  one  and  one  half  per  cent  of  sulfates  and  two  tenths  per  cent 
of  common  salt  in  4  feet  depth;  but  there  was  but  little  carbonate  of 
soda.  These  percentages  represent  236,800  pounds  of  sulfates  and 
35,200  pounds  of  common  salt  per  acre  in  that  depth.  Then,  too,  a  three- 
year-old  tree  at  Visalia,  6  feet  high,  suffered  but  little  except  in  height 
in  a  soil  having  .08  per  cent  of  carbonate  of  soda  or  an  average  of 
12,800  pounds  per  acre  in  4  feet  depth.  Doubtless  these  large  amounts 
of  alkali  were  largely  below  the  reach  of  the  tender  tree  roots  during  the 


BULLETIN  225]        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI. 


281 


first  year  of  growth  and  did  not  rise  until  the  bark  of  the  roots  was 
strong  enough  to  resist,  thus  giving  time  to  grow  downward  and  lat- 
erally away  from  the  alkali. 

The  results  thus  give  strong  evidence  of  the  importance  of  thorough 
and  deep  irrigation  of  Eucalyptus  and  other  orchards  in  alkali  lands 
to  keep  the  alkali  down  out  of  reach  of  the  roots  until  the  latter  them- 
selves can  develop  and  extend  beyond  the  alkali  zone. 


EFFECT  OE  ALKALI  ON  EUCALYPTUS  BOTRYOIDES. 

No  tests  were  made  with  the  botryoides  at  the  Tulare  Station.  A  tree 
identified  as  E.  botryoides  was  found  near  Kingsburg  in  a  soil  appar- 
ently strongly  alkaline  in  character;  it  looked  fairly  well,  better  than 
a  rostrata  standing  near,  but  seemed  to  show  some  slight  injurious  effect 
of  the  alkali.  Black  walnut  trees  in  an  adjoining  lot  looked  very 
badly,  half  of  their  leaves  being  dead.  The  ground  around  the  euca- 
lypts  had  been  well  cultivated. 

Another  botryoides,  about  twelve  years  old,  was  found  growing  in  an 
alkali  soil  near  Fresno;  the  top  was  dead  and  the  tree  in  a  very  bad 
condition  from  the  alkali  salts. 

Samples  of  the  soils  of  these  two  trees  were  taken  to  depths  of  four 
.feet  and  their  alkali  contents  ascertained  as  shown  in  the  following 
table : 

E.   BOTRYOIDES    IN   ALKALI    SOILS. 


Percentage  in  soil. 

Pounds  per  acre,  4  feet. 

Locality. 

Condition. 

CO 

Ss 
o 

O 

H 

F 
1 

Sulfates.  - 

a 
s  e> 

s°  2. 

ST  S 

g 

o 

o 
p 

Kingsburg 

Slightly   affected   

Tops  dead 

.04 
.08 

.05 

.04 

.01 

.03 

.10 
.13 

6,400 
9,600 

8,000 
6,400 

1,600 

4,800 

16,000 
20,800 

Fresno 

While  the  tree  from  Kingsburg  suffered  but  little  in  .05  per  cent  of 
carbonate  of  soda,  that  from  Fresno,  with  much  less  carbonate  in  the  soil 
but  with  much  more  common  salt,  was  severely  affected.  The  former 
tree  had  received  good  treatment,  and  it  is  to  be  presumed  that  the 
latter  had  not. 

The  age  and  height  reached  by  these  trees  would  indicate  that  with 
proper  irrigation  methods  the  botryoides  can  be  made  to  withstand  as 
much  as  .05  per  cent  of  carbonate  of  soda  in  its  soil  without  injury. 


282 


UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


EFfECT  OE  ALKALI  ON  EUCALYPTUS  ROBUSTA. 

Seedlings  of  the  Eucalyptus  robusta  were  not  planted  in  the  special 
alkali  plot  of  the  Tulare  Experiment  Station,  but  there  are  two  trees, 
one  large,  the  other  small,  growing  near  the  station  fence  in  the  Euca- 
lyptus row  which  are  many  years  old.  There  is  some  alkali  in  their 
soils  as  shown  in  the  analyses  given  in  the  table. 

In  his  search  through  the  San  Joaquin  Valley,  Mr.  Johnson  found 
five  trees  that  have  been  identified  by  Professor  Hall  as  robusta,  grow- 
ing in  alkali  soils.  One  at  Kingsburg,  about  five  years  old,  was  but 
slightly  affected,  though  it  had  received  no  cultivation  and  was  sur- 
rounded with  weeds  and  salt  grass ;  a  gravelly  hardpan  occurred  at  two 
feet  below  the  surface,  but  the  roots  of  the  tree  had  made  their  way 
through  it  into  the  soil  below. 

The  other  trees  were  found  near  Fresno;  No.  4  was  two  years  old, 
about  15  feet  high  and  showed  no  effect  of  the  alkali ;  No.  5  was  about 
12  feet  high,  had  received  no  cultivation,  and  was  somewhat  stunted 
in  growth,  though  otherwise  apparently  in  healthy  condition;  No.  6, 
six  years  old,  was  sickly  in  appearance  and  the  edges  of  its  leaves  were 
dead  though  the  tree  was  in  full  bloom.  No.  7,  eight  years  old,  also 
appeared  sickly.  Its  soil  contained  .07  per  cent  of  carbonate  of  soda,  or 
an  equivalent  of  about  11,200  pounds  per  acre  in  4  feet  depth ;  the  owner 
of  the  land  remarked  that  nothing  would  grow  upon  it  before  the  euca- 
lypts  were  planted. 

The  alkali  content  of  the  soils  of  these  trees  is  given  in  the  following 
table  : 

E.    ROBUSTA  ON   ALKALI    SOIL. 


H 


Locality. 


Tulare 

Tulare 

Kingsburg. 

Fresno 

Fresno  — 


Fresno 


Percentage  in  soil. 


Effect  of  alkali. 


Small  tree  

Large  tree 

Slight  effect  

Not    affected   

Somewhat    stunted. 

Sickly  

Sickly   


Pounds  per  acre,  4  feet. 


.03 
.02 
.04 
.06 
.03 
.04 
.07 


.03 
.08 
.02 
.04 
.04 
.04 


11,200 
22,400 
19,200 
8,000 
9,600 
14,400 
12,800 


4,800 
3,200 
6,400 
9,600 
4,800 
6,400 
11,200 


9,600 
4,800 
12,800 
3,200 
6,400 
6,400 
6,400 


30,400 
38,400 
20,800 
20,800 
27,200 
30,400 


The  treatment  given  the  trees  of  the  above  table  while  young  is  not 
known,  but  it  is  evident,  as  remarked  above,  that  if  proper  care  is  taken, 
and  irrigation  water  applied  in  sufficient  amount  to  keep  the  alkali  down 
several  feet  andenable  the  young,  tender  rootlets  to  pass  beyond  the 
danger  zone,  before  the  alkali  returns  to  the  surface,  a  good  healthy 


Bulletin  225]        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI. 


283 


growth  may  be  secured  in  presence  of  even  as  much  as  .06  per  cent  of 
carbonate  of  soda,  which  is  equivalent  to  nearly  10,000  pounds  per  acre. 
This  is  shown  by  tree  No.  4  from  Fresno. 

Common  salt  has  but  little  if  any  effect,  for  tree  No.  3  from  Kings- 
burg  has  withstood  as  much  as  .08  per  cent  (nearly  13,000  pounds  per 
acre),  even  without  cultivation  and  with  other  unfavorable  conditions. 

On  the  other  hand,  No.  7  seems  to  have  been  affected  by  .07  per  cent 
of  carbonate  of  soda  (nearly  12,000  pounds  per  acre  in  4  feet).  From 
this  we  would  judge  that  a  percentage  of  .06  of  carbonate  of  soda  is 
about  the  upper  limit  of  tolerance  on  the  part  of  the  robust  a. 


EFFECT  OF  ALKALI  ON  OTHER  SPECIES  OF  EUCALYPTUS. 

Species  of  Eucalyptus,  other  than  those  with  which  experiments  have 
been  made  in  the  alkali  plot,  are  growing  along  the  south  fence  of  the 
Tulare  Station,  having  been  planted  in  1888  and  have  reached  heights 
of  from  50  to  100  feet.  The  list  of  trees  in  the  row,  beginning  at  the 
corner  of  the  station  comprise  the  following  (as  identified  by  Prof.  H.  M. 
Hall  from  specimens  of  flowers,  etc.)  ;  the  amounts  of  alkali  salts  occur- 
ring in  their  respective  soils  to  a  depth  of  four  feet  is  given  in  the  table : 

Alkali  Salts  Under  Row  of  Eucalyptus  Along  the  Fence:  Tulare  Station. 


Percentage  in  soil. 


Species. 


D   P 


1 

Robusta 

.142 
.074 
.121 
.133 
.084 
.070 
.057 
.074 
.117 
.022 
.060 
.044 
.056 
.217 

■1 

Crebra   _ 

3 

Sideroxylon 

4 

Gunnii    

Gunnii    

6 

Sideroxylon 

Corynocalyx 

S 

Robusta    

9 

Gunnii    

10 

13 

Corynocalyx  

Rostrata    

14 

Sideroxylon 

15 

Rostrata  .. 

Amygdalina    

015 

.028 

.185 

017 

.019 

.109 

010 

.046 

.178 

007 

.046 

.186 

019 

.046 

.149 

014 

.037 

.121 

029 

.028 

.114 

024 

.060 

.158 

015 

.037 

.170 

009 

.019 

.049 

012 

.009 

.081 

015 

.037 

.093 

019 

.037 

.112 

017 

.019 

.253 

22,720 
11,840 

19,360 

21,280 

13,440 

11,200 

9,120 

11,840 

18,720 

3,520 

9,600 

7,040 

8,960 

34,720 


2.400 

4,480 

2,720 

3,040 

1,600 

7,360 

1,120 

7,360 

3,040 

7,360 

2,240 

5,920 

4,640 

4,480 

3,740 

9,600 

2,400 

5,920 

1,440 

3,040 

1,920 

1,440 

2,400 

5,920 

3,040 

5,920 

2,720 

3,040 

29,600 
17,600 
28,320 
29,760 
23,840 
19,360 
18,240 
25,180 
27,040 
8,000 
12,960 
15,360 
17,920 
40,480 


In  the  row  of  trees  the  amygdalina,  Gunnii  No.  4  and  the  rostral  a 
No.  1  were  growing  in  stronger  total  alkali  than  any  others,  while  the 
corynocalyx  No.  7  is  in  the  strongest  carbonate  of  soda,  .029  per  cent. 
The  soil  of  the  robusta  No.  8  has  the  highest  amount  of  common  salt, 
.06  per  cent,  the  equivalent  of  nearly  10,000  pounds  per  acre  in  4  feet. 

Young  seedlings  of  all  of  the  above  species  of  Eucalyptus,  excepting 
the  amygdalina,  botryoides,  sideroxylon,  Gunnii,  and  robusta,  have  been 


284  UNIVERSITY  OF   CALIFORNIA— EXPERIMENT   STATION. 

experimented  with  in  the  Tulare  Station  plot  and  the  results  are  given 
on  previous  pages  of  this  bulletin ;  the  robusta  and  botryoides,  on  which 
observations  were  made  in  other  parts  of  the  State,  are  also  discussed 
above  with  other  species. 

E.  sideroxylon.  There  are  three  trees  of  this  species  growing  in 
the  Eucalyptus  row  at  Tulare  as  shown  above  in  the  table,  but  in 
their  soils  there  is  but  a  small  amount  of  alkali  salts,  the  largest  being 
.178  per  cent.  The  highest  percentage  of  carbonate  of  soda  is  in  the 
soil  of  No.  14  where  we  find  .015  per  cent  or  the  equivalent  of  2,400 
pounds  per  acre,  which  is  quite  small  in  a  four-foot  column.  The 
largest  amount  of  common  salt  is  with  the  soil  of  the  same  tree  which 
contains  .046  per  cent,  or  nearly  7,500  pounds  per  acre  4  feet  depth. 

The  sideroxylon  can,  without  doubt,  withstand  the  effects  of  much 
larger  amounts  of  alkali  salts  than  found  under  these  trees. 

E.  Gunnii.  Seedlings  of  E.  Gunnii  were  not  planted  in  the  test  plot 
of  the  Tulare  Station,  and  the  only  trees  of  this  species  growing  in 
alkali  lands  that  we  know  of  are  the  three  in  the  row  along  the  station 
fence  at  Tulare,  as  given  in  the  above  table.  The  alkali  in  the  soil  of 
No.  4  is  greater  than  in  that  of  any  of  the  trees  of  the  row  (.186  per 
cent)  but  is  not  excessive.  The  highest  carbonate  of  soda  under  the 
Gunnii  is  .019  and  of  common  salt  .046  per  cent,  and  these  have  not 
produced  any  apparent  injury.  Both  the  sideroxylon  and  the  Gunnii 
can,  almost  without  doubt,  withstand  as  much  carbonate  of  soda  as  other 
species  of  eucalypts  which  has  thus  far  been  placed  at  .04  per  cent  in  a 
depth  of  three  feet. 

E.  amygdalina.— The  amygdalina  is  standing  in  a  soil  containing  the 
highest  total  alkali  of  the  group,  .253  per  cent,  or  about  40,000  pounds 
per  acre  in  4  feet  depth,  but  the  amounts  of  carbonate  and  common  salt 
are  only  .017  and  .019  per  cent  (2,700  and  3,000  pounds)  respectively. 
The  species  can  without  doubt  do  well  in  as  much  as  .04  per  cent  of 
carbonate  of  soda. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  285 

SUMMARY  OF  RESULTS. 

The  highest  percentage  of  carbonate  of  soda  found  in  the  soils  of  the 
respective  species  of  eucalypts,  and  the  condition  of  the  tree  in  presence 
of  these  percentages,  both  in  the  seedling  test-plot  at  Tulare  and  at  out- 
side places  are  given  in  the  following  summary: 


Tulare  seedlings:  soils  3  feet  deep. 

Trees  growing  elsewhere;  soils  4  feet  deep. 

Species. 

Carb. 

soda. 

per 

cent. 

Condition. 

Height. 

Carb. 

soda. 

per 

cent. 

Condition. 

Height. 

.10 
.08 
.07 

.08 
.07 

.07 
.08 

.08 
.05 

.07 
.06 

.07 
.05 

.07 
.05 

Dying  

6  inches 
10  inches 
6  inches 

36  inches 
24  inches 

18  inches 
4  inches 

18  inches 
6  inches 

18  inches 

8  inches 

30  inches 
48  inches 

20  inches 
24  inches 

.02 

Healthy   __    

Tall 

Dying      

Poor   growth— _ 
Good    

Rudis 

.09 
.08 

Good         

6  feet 

Leaves    dying., 
Dead  _  _    ..  ___ 

Corynocalyx  _ 

Leaves  dying- 
Dead  

.07 

Leaves  yellow  _.    

25  feet 

Dwarfed   

Dead 

.14 

.07 

.08 
.05 

Sickly;  8  years  old 

Good 

Good 

Leaves  dying... 
Dead  

Not  full  grown;  3  years  old 

Cornuta__  

Robust  a 

.07 
.06 

.05 

.02 

.02 
.02 

Sickly     

Not  affected 

6  feet 

Botrvoides 

Slightly  affected  

Sideroxylon  _  _ 

Large  tree  not  affected 

Gunnii 



Large  tree  not  affected 

Amvgdalina 

Large  tree  not  affected 

! 

Among  the  young  trees  at  Tulare  in  the  above  table  the  crebra  was 
exposed  to  the  highest  amount  of  carbonate  of  soda,  but  only  grew  a 
few  inches  and  finally  died.  The  rudis  alone  made  good  growth  in  as 
much  as  .08  per  cent,  though  with  .09  per  cent  in  an  outside  grove  it 
was  alive  but  not  growing.  The  rostrata  in  an  outside  grove  three  years 
old  had  its  growth  retarded  by  .08  per  cent,  but  at  Tulare  the  seedling 
made  good  growth  of  36  inches  in  presence  of  .07  per  cent.  The 
globulus  was  stunted  by  .14  per  cent,  made  less  than  half  growth  with 
.07  and  was  dead  with  .06  per  cent  of  carbonate  of  soda. 

The  highest  amount  of  carbonate  of  soda  found  in  any  soil  during 
this  investigation  was  .20  per  cent  (32,000  pounds  per  acre)  in  a  depth 
of  4  feet  in  a  Eucalyptus  plantation  near  Pixley.  A  two-year-old  tree 
growing  in  it,  not  identified  but  supposed  by  Mr.  Johnson  to  be  a  cory- 
nocalyx, had  made  a  growth  of  but  3  feet.     It  was  in  a  sandy  soil,  and 


286 


UNIVERSITY  OF   CALIFORNIA— EXPERIMENT   STATION. 


had  had  good  cultivation  and  irrigation,  which  had  evidently  kept  the 
corrosive  carbonate  of  soda  below  the  tender  surface  roots,  thus  affording 
a  good  illustration  of  what  proper  treatment  will  do  in  helping  a  seed- 
ling to  escape  severe  injury  in  a  soil  containing  large  amounts  "of  alkali 
salts.  The  next  highest  amount  of  carbonate  of  soda  given  in  the  tables 
above  was  that  of  .14  per  cent  in  which  a  globulus  was  slowly  growing. 

The  following  table  presents  the  highest  percentages  of  carbonate  of 
soda  found  in  the  soil  of  such  seedlings  of  each  species  of  Eucalyptus 
that  at  the  end  of  the  first  season  at  Tulare  had  reached  their  highest 
growth  and  remained  healthy  : 


Species. 


Height. 


Carbonat 
of  soda. 


Pounds  per  acre  of 
carbonate  of  soda. 


E.   rudis 


E.  crebra  _. 
E.    rostrata 


E.  globulus 

E.  corynocalyx 


36  inches 
24  inches 


inches 


48  inches 
36  inches 


30  inches 
18  inches 


30  inches 
24  inches 


E.  tereticornis  24  i 


E.   cornuta 


inches 


42  inches 
24  inches 


.08  per  cent 
.05  per  cent 

.07  per  cent 

.05  per  cent 
.07  per  cent 

.04  per  cent 
.04  per  cent 

.04  per  cent 
.04  per  cent 

.04  per  cent 

.03  per  cent 
.04  per  cent 


9,600 
6,000 

8,400  little  growth. 

6,000 
8,400 

4,800 
4,800 


4,800 
4,800 


4,800 


3,600 
4,800 


From  the  above  table  it  will  be  seen  that  the  E.  rudis  among  the  seed- 
lings at  Tulare,  reached  its  highest  growth,  unaffected,  in  a  higher  per- 
centage of  carbonate  of  soda  than  did  any  other  species ;  the  soil  of  this 
seedling  contained  .08  per  cent  of  the  carbonate  or  an  average  of  nearly 
10,000  pounds  per  acre  in  a  depth  of  3  feet.  This,  with  the  fact  that 
not  one  of  its  seedlings  was  killed  in  the  test  row  while  all  other  species 
lost  numbers  of  their  seedlings,  would  seem  to  place  the  rudis  as  first 
among  alkali-resistant  eucalypts. 

The  rostrata,  with  its  tall  growth  of  48  inches  in  .05  per  cent  of  the 
carbonate,  and  30  inches  in  .07  per  cent,  marks  it  as  next  to  the  rudis 
in  its  resistance  to  alkali  effects. 

While  the  crebra  seem  to  rank  next  to  the  rudis  with  its  .07  per  cent 
of  carbonate,  its  very  slow  growth  of  but  about  four  inches  in  the  season, 
and  the  general  injurious  effect  on  all  of  its  trees,  in  reality  places  it 
below  even  the  cornuta  at  the  bottom  of  the  list. 

The  other  species,  except  the  cornuta  and  crebra,  so  far  as  the  present 
records  go,  are  about  equal  in  their  tolerance  of  carbonate  of  soda,  and 
we  may  safely  place  the  amount  at  .04  per  cent  or  about  5,000  pounds 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  287 

per  acre  distributed  in  the  upper  3  feet  of  soil ;  or  possibly  6,500  pounds 
if  distributed  through  4  feet  depth. 

The  eucalypts  thus  seem  to  have  a  higher  toleration  for  carbonate  of 
soda  than  do  many  orchard  trees,  and  are  apparently  not  sensitive  to 
very  large  amounts  of  the  sulfates  and  of  common  salt  if  distributed 
through  the  upper  soil  instead  of  being  accumulated  on  the  surface. 


CONCLUSIONS. 

A  general  review  of  the  work  thus  far  done  with  regard  to  the  effect 
of  alkali  salts  upon  several  species  of  Eucalyptus  brings  out  the  follow- 
ing conclusions  based  upon  the  results  obtained: 

1.  The  limit  of  tolerance  of  alkali  salts  upon  the  part  of  the  Euca- 
lyptus is  greater  in  soils  well  taken  care  of  than  in  poorly  treated  ones. 
Care  in  the  cultivation  and  irrigation  of  the  young  trees  is  highly 
important  in  plantations  of  eucalypts,  as  well  as  in  other  cultures. 

2.  A  higher  percentage  of  alkali  salts,  and  especially  of  carbonate  of 
soda,  may  be  tolerated  by  young  Eucalyptus  if  the  alkali  be  kept  below 
the  roots  or  at  a  depth  of  several  feet,  until  the  roots  have  passed 
beyond  the  alkali  bed  both  downward  and  laterally,  and  the  bark  of  the 
roots  has  become  sufficiently  thick  to  resist  corrosion. 

3.  The  carbonate  of  soda  is  proven  by  the  observations  to  be  the  chief 
hurtful  ingredient  in  alkali.  The  sulfates  and  chlorids,  even  in  large 
amounts  have  but  little  injurious  influence  on  the  young  eucalypts,  so 
long  as  they  do  not  form  a  thick  crust  on  the  surface  of  the  ground ; 
the  globulus  grew  to  a  height  of  60  feet  on  the  levee  of  one  of  the  islands 
in  the  tule  marsh  lands  of  the  Sacramento  and  San  Joaquin  rivers,  the 
soil  of  which  contained  about  40,000  pounds  of  common  salt  in  a  depth 
of  two  or  three  feet.  The  carbonate  of  soda  may  be  neutralized  and 
changed  to  non-injurious  sulfates  by  the  application  of  sufficient 
amounts  of  finely  ground  gypsum  with  an  abundance  of  irrigation  water. 

4.  The  value  of  Eucalyptus  trees  being  dependent  on  their  size,  the 
seedling  should  not  be  planted  in  alkali  soil  having  such  a  percentage 
of  carbonate  of  soda  that  would  dwarf  or  even  retard  the  growth,  unless 
precautions  be  taken  to  keep  the  alkali  below  the  young  root  system  for 
a  couple  of  years  or  more.  A  percentage  of  from  .07  for  many  of  the 
species  and  .09  for  the  rudis  and  rostrata  seems  to  have  this  retarding 
effect  on  the  growth,  but  the  generous  application  of  gypsum  should 
counteract  this. 

5.  Of  the  species  of  eucalypts  tested  at  the  Tulare  Station,  the  rudis 
reached  its  best  growth,  in  a  higher  percentage  of  carbonate  of  soda 
than  did  any  of  the  others.  Its  .08  per  cent  is  equivalent  to  nearly 
10,000  pounds  per  acre  in  a  depth  of  3  feet. 

The  rostrata  stands  next  to  rudis  in  its  resistance  to  alkali  at  the 


288  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

Tulare  Station  (.07  per  cent)  while  the  globulus,  corynocalyx,  tereti- 
cornis,  and  cornuta,  each  reached  their  maximum  growth  in  but  .04 
per  cent  of  carbonate  of  soda,  being  apparently  retarded  by  a  larger 
amount. 

The  crebra,  while  apparently  healthy  with  as  much  as  .07  per  cent  of 
carbonate  of  soda,  had  made  scarcely  any  growth  in  the  first  season,  and 
can  hardly  be  called  an  alkali-resistant  species. 

6.  The  beneficial  effects  of  good  care  and  irrigation  are  shown  by  a 
tree  supposed  to  be  corynocalyx  growing  near  Fresno  in  a  soil  contain- 
ing as  high  as  .20  per  cent  of  carbonate  of  soda  in  a  depth  of  4  feet.  In 
this  instance,  the  alkali  had  evidently  been  largely  kept  away  from  the 
young  rootlets  by  the  abundant  irrigation  and  cultivation  of  several 
years  until  the  danger  point  had  been  passed. 

7.  In  general,  a  percentage  of  .04  of  carbonate  of  soda  in  3  feet  depth 
(or  about  5,000  pounds  per  acre)  was  easily  tolerated  without  injury  by 
each  of  the  species  of  eucalypts  tested  at  Tulare,  and  doubtless  will  be 
by  many  others. 

Further  observations  will  probably  place  the  limit  of  tolerance  at  a 
higher  figure  than  at  present  determined  for  the  several  species. 


BULLETIN  225]         TOLERANCE   OF   EUCALYPTUS   FOR    ALKALI.  289 

CULTURE  METHODS  AND  USES  OE  EUCALYPTUS. 

(Partial  Reprint  from  Bulletin   196.) 


[The  edition  of  Bulletin  196  of  this  station,  entitled  " Eucalyptus 
in  California/'  by  Mr.  Norman  Ingham,  in  charge  of  the  Santa  Monica 
Station,  has  been  entirely  exhausted,  and  the  request  for  copies  is  so 
great  that  it  has  been  thought  best  to  reprint  such  portions  of  it  as 
relate  to  cultural  methods  and  uses,  and  the  descriptions  of  those  species 
on  which  alkali  observations  have  been  made.  These  are  abstracted  in 
abbreviated  form,  substantially  as  given  by  Mr.  Ingham  in  his  bulletin. 
Extracts  have  also  been  made  from  the  admirable  publications  of  Mr. 
Abbot  Kinney  of  Los  Angeles  and  Baron  von  Mueller  of  Australia,  in 
which  they  describe  the  numerous  species  of  Eucalyptus.  Mr.  Ingham, 
however,  cautions  eucalyptus  planters  not  to  rely  on  Australian  expe- 
rience as  plantings  in  California  seem  to  show  material  differences  in 
success.] 

Eucalyptus  planting  has  now  passed  the  experimental  stage  and  may 
be  considered  without  question  as  a  commercial  proposition.  The  value 
of  the  crop  and  the  possibilities  of  growing  it  in  California  have  beei] 
sufficiently  demonstrated  to  make  judicious  plantings  even  on  a  large 
scale  perfectly  safe,  with  an  assurance  of  sure  and  reasonably  large 
profits.  It  is  important,  however,  for  the  planter  to  consider,  in  the 
light  of  the  best  information,  the  nature  of  the  product  which  he  will 
produce,  or,  in  other  words,  the  market  which  he  will  attempt  to  supply 
with  the  Eucalyptus  trees. 

Since  the  introduction  of  the  first  species  of  Eucalyptus,  the  seeds  of 
other  species  have  been  imported  each  year  by  seedsmen,  nurserymen, 
and  in  many  cases  ranch  owners  until  at  the  present  time  there  are  grow- 
ing in  the  State  nearly  one  hundred  species.  The  University  of  Cali- 
fornia has  seventy  named  species  growing  on  the  forestry  station 
grounds  at  Santa  Monica,  California ;  there  are  specimen  trees  of  nearly 
every  species  over  ten  years  of  age  and  bearing  seed  at  the  present  time, 
while  there  are  young  trees  of  all  the  promising  lumber  eucalypts. 

From  this  large  collection  there  can  be  selected  species  that  will  grow 
on  nearly  any  soil  in  a  frostless  region,  while  there  are  a  few  that  can 
endure  a  temperature  from  20°  F.  to  120°  F,  and  at  different  altitudes; 
but  with  these  trees  it  is  as  with  any  other,  there  is  one  location  best 
adapted  to  the  greatest  development;  it  may  be  a  situation  near  the 
coast  in  a  foggy  atmosphere,  the  river  bottoms,  the  inland  valleys  or  in 
swamps.  Care  should  be  taken  in  selecting  a  species  for  any  certain 
locality,  that  the  conditions  there  are  the  ones  that  will  bring  the 
species  in  question  to  the  highest  point  of  development. 


90 


UNIVERSITY   OF   CALIFORNIA— EXPERIMENT   STATION, 


EUCALYPTUS  FOR  TIMBER. 

The  wood  of  the  different  species  of  Eucalyptus  varies  from  a  wood 
as  soft  as  that  of  our  pines,  to  very  hard,  closed-grained  and  variously 
colored  kinds  equal  to  our  native  oaks  and  hickories.  Among  the  large 
number  of  species  may  be  found  some  that  can  be  substituted  for  nearly 
all  our  present  commercial  woods,  although  the  Eucalyptus  wood  is 
harder  to  work. 

Eucalyptus  timber  is  more  costly  to  cut  and  mill  than  any  of  our 
native  hardwoods;  in  planing,  the  lumber  of  many  of  the  species  has 
a  tendency  to  chip  on  account  of  the  irregular  grain,  while  that  of  all 
of  the  species  under  the  most  careful  handling  season-cracks  more  or  less 
on  the  ends.  This  fault  can  be  overcome  by  having  the  logs  sawed  a 
foot  or  two  longer  than  the  finished  product  needs  to  be  so  that  the 
season-cracked  ends  can  be  removed.  Very  little  trouble  is  experienced 
in  seasoning  the  lumber  if  the  trees  are  cut  down  during  the  winter 
months  and  sawed  while  green,  and  the  lumber  then  piled  in  high  tiers 
to  obtain  weight,  in  some  places  protected  from  the  wind  and  sun. 

Strength  Tests  of  Eucalyptus. — We  reproduce  the  following,  bearing 
on  the  strength  of  several  species  of  Eucalyptus  timber : 

United  States  Department  of  Agriculture, 
Forest  Service. 
Trade  Bulletin  S.  October  S,  1900. 

eucalyptus  for  timber. 

The  wood  of  the  eucalypts  has  not  been  extensively  used  by  manufacturers  in 
the  United  States,  because  the  supply  has  not  been  sufficient  to  establish  a  market. 
Blue  gum,  the  most  common  species  in  California,  has,  however,  competed  with  black 
locust  for  insulator  pins,  has  given  satisfactory  service  in  chisel  and  hammer  handles. 
and  has  been  used  locally  for  wagon  tongues,  axles,  spokes,  hubs,  and  felloes.  It  is 
hard,  strong,  and  tough. 

In  cooperation  with  the  State  of  California,  the  Forest  Service  recently  completed 
a  study  of  the  mechanical  and  physical  properties  of  the  common  eucalypts.  The 
tests,  made  at  the  State  University  at  Berkeley,  were  to  determine  whether  Euca- 
lyptus can  be  substituted  for  some  of  the  hard  woods  that  are  becoming  difficult  to 
obtain. 

Blue  gum  is  by  far  the  fastest  growing  species.  The  height  and  diameter  of  trees 
from  which  the  test  pieces  were  taken  is  given  in  the  following  table.  All  the  trees 
were  about  fifteen  years  old  : 


• 

Species. 

Diameter, 

inches. 

Height, 

Common  name. 

Botanical  name. 

feet. 

Eucalyptus  globulus.  .... 

30 
15 
16 
12 

10 

8 

101 

Eucalyptus  corynocalyx    

73 

Eucalyptus  diversicolor 

72 

Eucalyptus  viminalis 

Eucalyptus  rostrata 

Eucalyptus  punctata 

60 

47 

43 

Eucalyptus  resinifera 

38 

Bulletin  225]       tolerance  of  eucalyptus  for  alkali. 


291 


An  important  point  in  considering  the  value  of  commercial  plantations  of  euca- 
lyprs  is  brought  out  in  the  next  table,  which  shows  that  the  fastest  growing  species 
are  also  the  strongest.     The  tests  were  made  upon  kiln-dried  material. 


Species. 


Compression  parallel 

Rending. 

to  grain. 

Modulus 

Crushing 

Age  in 

Number 

of  rupture 

Xumber 

strength. 

years. 

of  tests. 

pounds  per 

of  tests. 

pounds  per 

5 

square  inch. 

square  inch. 

15 

25,344 

n 

11,290 

30 

12 

23,265 

15 

12,310 

15 

3 

19,267 

10 

10,908 

15 

8 

18,386 

17 

8,795 

15 

28 

16,900 

34 

8,190 

15 

4 

14,550 

2 

7,920 

15 

9 

14,380 

6 

7,723 

15 

12 

13,093 

20 

7,309 

Sugar  gum  .._ 

Blue  gum 

Leather-jacket 

Karri  

Blue  gum 

Red  mahogany 

Red  gum 

Manna  gum  _. 


A  comparison  with  Forest  Service  tests  on  hickory  shows  that  30-year-old  blue 
gum  is  stronger  than  XXX  hickory,  and  that  15-year-old  sugar  gum  is  nearly  as 
strong  as  black  hickory  and  91  per  cent  as  strong  as  second-growth  hickory. 

The  wood  of  very  young  and  sappy  trees  is  apt  to  warp,  but  that  from  more 
mature  growth  can  be  easily  handled  to  prevent  warping.  Early  seasoning  should 
proceed  slowly.  Open  piling  is  desirable ;  the  stacks  should  be  high  to  secure  weight, 
and  should  be  covered. 

Several  of  the  Eucalyptus  grow  rapidly  in  California,  and,  under  forest  condi- 
tions, form  straight,  tall  poles  free  from  branches.  They  have,  therefore,  especial 
value  as  timber  trees. 

EUCALYPTUS  FOR  FUEL. 

The  wood  of  most  of  the  eucalypts  makes  good  fuel.  A  grove  of  blue 
gums  five  years  old,  set  out  6  by  6  feet  apart,  under  favorable  condi- 
tions should  yield  from  50  to  80  cords  of  wood  per  acre,  while  at  ten 
years  of  age  80  to  150  cords  may  be  expected.  Groves  under  irrigation 
will  undoubtedly  do  better  than  the  above  figures  indicate,  while  the 
quality  of  the  land  will  also,  of  course,  have  a  great  influence.  The 
cost  of  working  up  the  standing  trees  into  fuel  ready  to  burn  varies 
somewhat  with  the  age  and  species  of  the  trees. 

#  EUCALYPTUS  FOR  OIL. 

The  leaves  and  twigs  of  the  tree,  when  distilled,  produce  an  oil  which 
has  great  medicinal  properties  and  is  used  quite  extensively  in  medicine 
at  the  present  time.  This  oil  is  a  non-irritant  antiseptic,  which  can 
be  used  without  the  slightest  injury  on  all  the  tissues  of  the  body  and 
internally  in  very  small  quantities.  The  amount  of  oil  that  can  be 
extracted  from  a  certain  number  of  pounds  of  leaves  and  twigs  varies 
with  the  locality  in  which  the  grove  is  situated,  in  the  different  trees 
according  to  their  positions  in  the  grove  and  in  the  different  species  of 
Eucalyptus.  The  latter  is  also  true  in  regard  to  its  medicinal  prop- 
erties. 


4— bul  225 


292  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

The  leaves  from  the  brush  of  ten  cords  of  wood,  cut  from  the  globulus 
five  years  of  age  distil  from  one  and  a  half  to  two  and  a  half  gallons  of 
oil,  or  two  tons  of  leaves  and  twigs  will  produce  from  three  to  four 
gallons. 

According  to  Von  Mueller,  the  following  percentages  of  oil  are 
obtained  from  the  foliage  of  a  number  of  species: 


Species. 


Volatile  oil. 


E.   amygdalma 1  3.313  per  cent 

E.  oleosa  1250  per  cent 

E.  leucoxylon 1060  per  cent 

E.  goniocalyx  0.9U  per  cent 

E.  globulus 


E.  obliqiu 


0.719  per  cent 
0.500  percent 


The  lesser  quantity  of  oil  of  E.  globulus  is,  however,  compensated 
for  by  the  vigor  of  its  growth  and  the  early  copiousness  of  its  foliage. 
E.  rostrata,  though  one  of  the  poorest  in  oil,  is  nevertheless  important 
for  malarial  regions,  as  it  will  grow  well  on  periodically  inundated 
places  and  even  in  stagnant  waters  not  saline.  Eucalyptus  oils  dissolve 
the  following,  among  other  substances  for  select  varnishes  and  other 
preparations;  camphor,  pine  resins,  mastic,  elemi,  sandarac,  kauri, 
dammar,  asphalt,  benzoe,  copal,  amber,  shellac,  caoutchouc,  also  wax 
but  not  gutta-percha.  These  substances  are  arranged  in  the  order  of 
greatest  solubility. 

THE  EUCALYPTS  AS  BEE  PASTURE. 

All  of  the  eucalypts  have  more  or  less  value  as  bee  pasture  when  in 
bloom,  and  from  the  large  number  of  species  growing  in  the  State  it  is 
possible  to  select  a  group  that  will  furnish  bloom  for  the  bees  to  work 
on  the  year  round.  If  the  natural  pastures  are  good  for  all  but  a  short 
period  each  year,  it  is  possible  to  select  one  or  two  species  of  Eucalyptus 
that  will  fill  in  that  time. 

The  list  given  below  is  made  up  from  the  data  collected  from  two 
years'  observation  of  the  blooming  periods  of  the  Eucalyptus  species  on 
the  Forestry  Station  ground.  The  names  of  the  species  are  put  down 
for  the  months  when  the  most  of  the  trees  of  that  species  are  in  bloom, 
although  there  are  instances  in  every  species  where  some  one  individual 
specimen  will  be  found  blooming  at  an  entirely  different  period,  or  per- 
haps twice  during  the  year.  Some  of  the  species  have  been  considered 
injurious  to  bees,  but  we  have  never  been  able  to  find  dead  bees  under 
the  tree.  The  bees  seem  to  have  a  preference  for  the  white  or  greenish 
white  flowers : 

January :  globulus,  leucoxylon,  siderophloia,  robust  a,  and  melliodora. 

February :  globulus,  robusta,  polyanthema,  leucoxylon,  and  mellio- 
dora. 


Bulletin  225]       TOLERANCE  OF  EUCALYPTUS  FOR  ALKALI.  293 

March:  globulus,  robusta,  leucoxylon,  polyanthema,  melliodora,  and 
sideroxylon  var.  rosea. 

April:  leucoxylon,  melliodora,  Gitnnii,  polyanthema,  and  Stuartiana. 

May :  melliodora,  Gunnii,  maculata,  comuta,  rostrata,  and  tereti- 
cornis. 

June:  melliodora,  macidata,  comuta,  tereticornis,  rostrata,  and  cit- 
riodora. 

July:  citriodora,  tereticornis,  rostrata,  viminalis,  comuta,  and  euge- 
n  10 ides. 

August:  viminalis,  comuta,  Lehmannii,  eugenioides,  calophylla, 
corynocalyx,  and  resinifera. 

September:  Lehmannii,  corynocalyx,  calophylla,  and  resinifera. 

October :  calophylla,  corynocalyx,  and  siderophloia. 

November:  corynocalyx,  siderophloia,  leucoxylon,  and  robusta. 

December :  globidus,  robusta,  leucoxylon,  and  sideroxylon  var.  rosea. 

EUCALYPTUS  ADAPTED  TO  SPECIAL  PURPOSES. 

The  species  whose  wood  is  the  most  durable  in  the  soil : 

Eucalyptus  rostrata,  tereticornis,  rudis,  diversicolor,  sideroxylon  var. 
rosea,  corynocalyx,  citriodora,  and  crebra. 
The  lumber  species: 

All  of  the  species  described  herein   are  valuable   as  lumber  trees, 
although  the  four  following  are  considered  the  best  among  the  eucalypts 
as  commercial  lumber  trees :  Eucalyptus  globulus,  rostrata,  tereticornis, 
and  corynocalyx. 
The  species  for  fuel  alone : 

All  of  the  species  are  of  more  or  less  value  for  wood,  but  the  following 
two  species  will  produce  more  wood  than  any  of  the  others  on  any  good 
land.     These  two  are  the  common  blue  gum,  Eucalyptus  globulus,  and 
viminalis,  the  two  most  rapid  growing  gums  we  have  in  this  country. 
The  most  frost-resistant  species : 

Eucalyptus   rostrata,   globidus,   viminalis,    tereticornis,   sideroxylon, 
crebra,  rudis,  robusta,  resinifera,  and  Stuartiana. 
Drought-resistant  species : 

Eucalyptus  corynocalyx,  microtheca,  polyanthema,  and  comuta. 

POTASH  IN  EUCALYPTUS. 

The  potash  obtainable  from  the  ashes  of  various  eucalypts  varies  from 
5  to  27  per  cent.  One  ton  of  fresh  foliage  of  E.  globidus  yields  about 
84-  pounds  of  pearl-ash  ;•  a  ton  of  the  green  wood,  about  2\  pounds ;  of 
dry  wood  about  4^  pounds. 


294  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

PLANTING  AND  CULTIVATION  OF  EUCALYPTUS. 

Quality  of  Soil  for  Eucalyptus  Planting. — The  idea  is  too  prevalent 
that  Eucalyptus  growing  is  exclusively  a  proposition  for  cheap,  dry, 
or  poor  land.  It  is  true  that  the  trees,  especially  certain  species,  .will 
live  and  grow  fairly  well  under  conditions  where  no  other  crop  could 
be  considered,  and  if  the  object  is  merely  the  utilization  of  such  land  to 
the  best  advantage  Eucalyptus  planting  may  be  wise  and  somewhat 
profitable.  For  one,  however,  who  is  buying  land  for  this  purpose,  or 
one  who  already  has  fairly  good  land  capable  of  irrigation  or  naturally 
moist,  it  is  becoming  more  and  more  apparent  that  good  land,  capable 
of  culture  and  irrigation,  will  produce  far  more  profitable  returns  on 
the  investment  by  reason  of  the  enormously  more  rapid  growth  and 
greater  wood  production  of  the  trees.  Under  such  conditions  a  crop 
of  trees  may  be  produced  and  marketed  and  the  land  then  cleared  for 
other  purposes,  or  the  stumps  allowed  to  sprout  for  a  second  crop,  when 
on  poor,  dry  land,  trees  of  the  same  age  would  not  pay  for  cutting. 

METHODS  OF  GROWING  EUCALYPTUS. 

The  necessary  conveniences  for  the  propagation  of  the  seedlings  are 
as  follows :  seed  boxes  or  flats,  a  good  soil,  seed  true  to  name,  plenty  of 
water  convenient  to  all  flats,  and  in  most  localities  a  shade  for  the  young 
plants  from  the  sun  is  required. 

The  Soil  for  the  Seed-bed. — It  has  been  proven  that  Eucalyptus  seeds 
will  germinate  and  grow  in  nearly  any  soil,  from  a  clear  beach  sand 
to  adobe,  but  the  best  results  are  obtained  if  the  seeds  are  sown  in  a  light 
loam ;  in  the  transplanting  flats  a  medium  loam,  mixed  with  about  one 
fourth  of  well  rotted  manure,  should  be  used. 

Shade  for  the  Young  Plants. — Where  a  large  number  of  plants  are 
to  be  grown,  a  lath  house,  with  the  laths  spaced  their  own  width  apart 
for  the  protection  of  the  young  plants  from  the  midday  sun,  will  be 
found  more  convenient  than  lath  or  cheese  cloth  screens  laid  on  small 
frames  above  the  flats,  as  the  labor  required  to  move  them  each  time 
the  plants  are  watered  would  amount  to  a  large  item  of  expense  during 
the  growing  season.  The  lath  house  or  the  screens  will  also  protect 
the  seed  flats  from  the  ravages  of  the  birds  and  the  young  plants  from 
the  frosts  (if  not  too  severe)  during  the  cold  weather  of  the  winter 
months,  before  the  time  for  setting  in  the  field. 

Time  to  Sow  the  Seed. — The  time  to  sow  the  seed  varies  somewhat 
with  the  locality,  but,  as  a  general  rule,  the  seed  should  be  sown  by  the 
latter  part  of  June  or  first  of  July,  and  the  seedlings  from  these  sow- 
ings will  be  large  enough  to  be  set  out  in  the  field  the  following  spring, 
if  they  receive  proper  care  while  young. 

Methods  of  Sowing  the  Seed. — The  seed  is  generally  sown  broadcast 
in  the  seed-flats  and  the  young  plants  transplanted  once  before  being 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  295 

set  in  the  field ;  while  others  sow  the  seeds  in  hills  and  practice  thinning 
instead  of  transplanting  before  setting  out  in  the  field.  With  either 
of  these  methods  the  flat  is  filled  to  a  depth  of  two  and  one  half  inches 
with  the  prepared  soil,  pressing  it  down  firmly  in  the  boxes,  the  seed  is 
sown  and  covered  to  a  depth  of  not  over  one  fourth  of  an  inch  with  the 
same  soil,  sand  or  sawdust,  pressing  the  covering  firmly.  The  number 
of  fertile  seeds  of  any  species  to  the  pound  is  very  high ;  the  average 
number  of  transplanted  plants  raised  to  the  pound  is  12,000.  The  seed- 
flats  should  be  kept  damp  through  the  heat  of  the  day,  until  the  young 
plants  break  through  the  ground,  then  care  must  be  taken  not  to  use  too 


Fig.    7. — Eucalyptus  seedlings,  rudis  and  viminalis. 

much  water  and  that  there  is  good  circulation  of  air  over  the  flats,  or  the 
fungous  disease  "damping  off"  is  liable  to  occur.  This  disease  is  most 
general  on  damp,  cloudy  days,  and  where  the  plants  are  watered  late  in 
the  evening.  Some  species  most  susceptible  to  damping  off  are  the  E. 
corymbosa,  citriodora,  calophylla,  ficiofolia,  and  globulus. 

Transplanting. — The  seeds  that  have  been  sown  broadcast  in  the 
fiats  can  be  transplanted,  when  the  plants  are  two  or  three  inches  high, 
to  other  flats  of  prepared  soil  and  spaced  from  one  and  a  fourth  to  two 
inches  apart;  the  soil  should  be  kept  damp  and  the  plants  protected 
from  the  direct  rays  of  the  sun  for  a  few  days. 

The  time  to  set  the  plants  in  the  field  varies  with  the  climatic  condi- 
tions or  localities,  and  whether  the  plants  are  to  receive  irrigation  or  not. 
In  localities  where  frosts  are  common  through  the  winter  months,  it  is 


296  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 

advisable  to  set  the  trees  out  as  early  in  the  spring  as  possible  without 
endangering  them  to  a  late  frost  and  still  have  them  receive  the  benefits 
of  the  late  rains,  so  that  they  will  have  a  full  season's  growth  to  with- 
stand the  frosts  of  the  following  winter.  If  trees  are  to  be  irrigated 
they  can  be  set  out  later  in  the  season  without  danger  of  loss  from  want 
of  moisture. 

The  size  of  the  plants  when  set  out  in  the  field  should  not  be  under  six 
or  over  ten  inches  in  height,  to  secure  a  good  stand.  The  land  should 
be  thoroughly  plowed  and  harrowed  before  planting.  The  distance 
apart  at  which  the  seedlings  should  be  planted  depends  upon  the  species 
of  Eucalyptus,  the  soil,  the  distance  to  water  and  whether  the  trees  are 
to  be  grown  for  fuel,  ties,  or  lumber.  Some  of  the  species  are  naturally 
straight-growing  trees,  while  others  grow  out  of  the  perpendicular  unless 
set  in  close  plantings.  In  a  rich,  heavy,  loam  soil  they  may  be  planted  as 
close  as  6  by  6  feet  or  if  irrigated  4  by  8  feet ;  on  lighter  soil  8  by  8  feet 
is  the  proper  distance,  or  6  by  10  if  irrigation  is  practiced.  The  close 
planting  has  a  tendency  to  sacrifice  the  diameter  growth  in  favor  of 
height,  also  making  more  erect  trees  and  forming  a  perfect  canopy  with 
their  crowns  that  will  shade  the  soil,  nearly  preventing  evaporation  of 
the  soil  water. 

Cultivation  of  the  young  trees  should  be  carried  on  as  long  as  possible 
without  danger  of  injuring  them;  they  can  generally  be  cultivated  for 
the  first  season  and  part  of  the  second  before  the  limbs  of  the  trees 
spread  out  and  interlap  so  as  to  make  it  impossible  to  drive  between 
the  rows. 

Thinning  of  the  Young  Trees. — It  is  a  self-evident  fact  that  to  grow 
large  trees  for  lumber  a  greater  space  than  6  by  6  feet  is  needed  for 
each  tree  to  reach  a  large  diameter,  but  at  the  same  time  it  would  be 
good  management  to  set  out  just  the  number  of  trees  to  the  acre  which 
are  expected  to  mature.  Trees  are  killed  by  gophers  and  rabbits  and 
by  extremes  of  temperature,  and  it  is  practically  impossible  to  replant 
in  the  missing  spaces  after  the  trees  are  one  year  old.  A  planting  upon 
any  good  soil  may  with  advantage  be  set  out  6  by  6  feet  apart  and  at  the 
end  of  the  first  year  a  rigid  thinning  should  be  started,  removing  with 
a  grub  hoe  all  weak,  inferior  or  injured  trees.  This  thinning  should  be 
carried  on  until  only  the  strong  and  healthy  trees,  or  a  certain  number, 
remain  to  the  acre. 

The  value  of  a  plantation  when  ten  years  old  will  depend  most  largely 
on  the  care  it  has  received  during  the  first  four  or  five  years  of  its 
growth.  One  of  the  most  essential  points  in  regard  to  the  growing  of 
perfect  trees  is  that;  they  start  to  grow  erect  with  clean  trunks  the  first 
few  years.  Some  trees  will  naturally  start  in  this  way,  while  others 
fork,  producing  a  number  of  lateral  branches  on  their  trunks ;  each  year 


Bulletin  225]       tolerance  of  eucalyptus  FOR  alkali. 


297 


all  limbs  that  have  a  tendency  to  deform  the  trees  should  be  removed. 
After  the  third  or  fourth  year  the  trees  will  have  grown  to  such  a  height 
that  to  remove  the  limbs  may  prove  impracticable  in  most  cases,  and  then 
the  poorer  trees  should  be  removed  for  wood  or  stakes  to  allow  the 
remainder  a  larger  area  of  soil  to  draw  upon  and  a  greater  space  above 
ground  to  extend  their  branches.  At  this  time  the  trees  on  an  acre  can 
be  reduced  to  a  certain  number,  leaving  those  to  grow  for  telephone 
poles,  ties  or  lumber ;  or  the  entire  grove  may  be  cut  for  stakes  and  wood. 
Sprouts. — Sprouts  will  start  from  the  stumps  in  from  three  to  six 
weeks  from  the  date  the  trees  are  cut  down,  in  any  month  of  the  year. 
The  number  of  sprouts  to  the  stump  is  generally  large  and  varies  with 
the  species  as  shown  in  the  following : 


.Species 


Diameter 

Number 

Height 

of  stump. 

of  sprouts. 

of  sprouts. 

3    feet 

15 

71  inches 

5|  feet 

59 

71  inches 

11    feet 

16 

65  inches 

5J  feet 

35 

;.2  inches 

41  feet 

55 

47  inches 

7|  feet 

21 

45  inches 

5    feet 

42 

45  inches 

4J  feet 

2 

42  inches 

5J  feet 

52 

41  ',  aches 

54  feet 

8 

41  inches 

polyanthema 
stuartiana  .. 

viminalis 

corynocalyx  . 
siderophloia 

globulus  

punctata  __. 
tereticornis  . 
leucoxylon  _. 
rostrata   


The  stump  of  the  globulus  had  been  driven  over  and  many  of  the 
sprouts  destroyed.  To  obtain  the  largest  profits  from  the  sprout  growth 
in  the  shortest  time,  it  is  necessary  to  go  over  the  planting,  when  the 
sprouts  are  from  six  months  to  a  year  old,  and  remove  all  but  two  to  four 
of  the  largest  and  most  erect  growing,  leaving  them  well  spaced  around 
the  stump ;  if  all  of  the  sprouts  are  allowed  to  remain  their  growth  is 
retarded. 

The  number  of  cords  per  acre  at  the  second  cutting  is  greater  for  the 
same  length  of  time,  and  is  due  to  the  fact  that  the  three  or  four  sprouts 
make  a  more  rapid  growth  than  the  parent  tree  because  of  a  fully 
developed  root  system  which  is  capable  of  supplying  the  food  to  a 
mature  tree. 


298  UNIVERSITY  OF  CALIFORNIA — EXPERIMENT  STATION. 

DESCRIPTION  OP  SPECIES  OF  EUCALYPTS. 

Mr.  Ingham  selects  the  following  eighteen  of  the  many  species  of 
Eucalyptus  as  being  the  most  promising  for  commercial  planting  in 
California,  and  describes  each  in  his  bulletin: 

E.  botryoides  E.  viminalis 

cary no  calyx  citriodora 

crebra  corymbosa 

globulus  diversicolor 

robusta  leucoxylon 

rostrata  polyanthema 

rudis  punctata, 

sideroxylon  var.  rosea  resinifera 

tereticornis  siderophloia 

Those  of  the  first  column  comprise  the  species  which  have  been  tested 
more  or  less  as  to  their  tolerance  for  alkali  salts,  and  whose  descriptions 
by  Mr.  Ingham  are  repeated  in  this  bulletin.  To  these  are  added  E. 
Gunnii  and  amygdalina  from  the  publications  of  Mr.  Abbot  Kinney  and 
Baron  von  Mueller.  The  illustrations  given  of  these  species  are  from 
the  bulletin  of  Mr.  Ingham. 

For  fuller  details,  and  for  descriptions  of  other  species  than  given 
here,  those  interested  are  referred  to  the  publications  of  Professor 
McClatchie  and  Messrs.  Abbot  Kinney,  von  Mueller,  and  Ingham. 

Eucalyptus  Amygdalina.     Brown  or  White  Peppermint  Tree. 

The  following  description  of  this  important  species  of  Eucalyptus 
is  given  by  Baron  von  Mueller.  In  sheltered,  springy,  forest  glens  it 
attains  exceptionally  a  height  of  over  400  feet  there  forming  a  smooth 
stem  and  broad  leaves,  producing  seedlings  of  a  foliage  different  from 
the  ordinary  form  of  amygdalina,  which  occurs  in  more  open  country 
and  has  small,  narrow  leaves  and  a  rough?  brownish  bark.  The  former 
species  or  variety,  which  has  been  called  E.  r  eg  nans,  represents  probably 
the  loftiest  tree  on  the  globe,  attaining  a  height  of  415  feet  with  a  diam- 
eter of  ]  5  feet,  a  considerable  distance  above  ground.  Another  tree  meas- 
ured 69  feet  in  circumference  at  the  base  of  the  stem;  at  12  feet  above 
ground  it  had  a  diameter  of  14  feet,  at  78  feet  a  diameter  of  9  feet ;  at 
144  feet  a  diameter  of  8  feet,  and  at  210  feet  a  diameter  of  5  feet.  The 
wood  is  fissile,  well  adapted  for  shingles,  rails,  staves,  inner  building 
material  and  many  other  purposes,  but  it  is  not  a  strong  wood.  That 
of  the  smaller,  rough,  barked  variety  has  proved  lasting  for  fence  posts. 

It  has  endured  tjae  frosts  of  the  milder  parts  of  England  with  E. 
Gunnii  and  cordata.  In  New  Zealand  it  has  survived  the  cold  where 
E.  globulus  succumbed.     This  species  yields  more  volatile  oil   (3.3  per 


BULLETIN  225]        TOLERANCE    OF   EUCALYPTUS   FOR   ALKALI.  299 

cent  in  the  foliage)   than  any  other  hitherto  tested  and  is  therefore 
largely  chosen  for  distillation. 

Mr.  Abbot  Kinney  says  that  while  E.  amygdalina  of  Australia  is  the 
tallest  tree  in  the  world,  yet  the  amygdalina  in  southern  California 
has  in  no  case  equalled  in  size  local  blue  gums.  Its  manner  of  growth 
here  gives  little  prospect  that  it  will  ever  surpass  E.  globulus. 

Eucalyptus  Botryoides.     Bastard  Mahogany. 

From  East  Gippsland  to  South  Queensland.  Vernacular  name  Bas- 
tard Mahogany,  and  a  variety  called  Bangalay,  the  latter  generally 
found  on  coast  sands.  One  of  the  most  stately  among  an  extensive  num- 
ber of  species  remarkable  for  its  dark-green  shady  foliage.  It  delights 
in  river  banks,  but  it  will  thrive  also  on  ground  with  stagnant  moisture. 
Grows  splendidly  at  the  city  of  Algiers  (Prof.  Bourlier).  Stems  attain 
a  height  of  80  feet  without  a  branch  and  a  diameter  of  8  feet.  The 
timber  usually  sound  to  the  center,  adapted  for  waterworks,  wagons, 
particularly  for  felloes,  also  knees  of  boats.  Posts  formed  of  it  are  very 
lasting,  as  no  decay  was  observed  in  fourteen  years ;  it  is  also  well 
adapted  for  shingles.     (Von  Mueller.) 

Mr.  Norman  Ingham,  in  charge  of  the  Santa  Monica  Station,  in  Bulle- 
tin No.  196  of  this  Experiment  Station,  says  of  the  botryoides:  Th^ 
trees  of  this  species  are  very  erect  in  growth,  but  branched ;  the  bark  of 
the  trunks  of  the  old  trees  is  reddish-brown  in  color,  rough  and  nearly 
persistent;  the  limbs  are  generally  smooth,  shedding  their  bark  in  long 
strips.  The  leaves  are  lance-shaped,  leathery  in  texture;  in  color  the 
upper  surface  is  a  dark  green,  while  the  lower  surface  is  much  paler. 
The  flower  clusters  are  borne  laterally  on  compressed  stalks.  The  seed 
cases  are  five  to  seven  in  number,  deep,  cup-shaped  and  stemless. 

The  timber  of  this  species  is  considered  by  the  Australian  writers  to 
be  one  of  the  best  of  eucalypts,  when  it  is  grown  where  there  is  plenty  of 
water.  It  makes  the  best  of  wind-breaks  and  is  one  of  the  best  eucalypts 
to  use  as  a  shade  tree. 

Eucalyptus  Corynocalyx.     Sugar  Gum. 

Trees  of  this  species  in  close  planting  grow  erect,  having  a  very  open 
crown,  while  individual  specimens  branch  low,  with  the  branches  scatter- 
ing. The  bark  of  the  trunks  of  the  old  trees  is  deciduous,  and  of  a 
scaly  appearance,  due  to  the  unequal  flaking  off  at  different  times  of  the 
year.     In  color  it  varies  from  a  cream  to  a  dark  gray. 

The  branches  are  smooth,  shading  off  in  color  to  a  light  green,  while 
the  twigs,  young  seedlings  and  sprouts  are  of  a  reddish  hue.  The  leaves 
of  the  young  plants  are  ovate,  dark  green  in  color  on  the  upper  side  of 
the  leaf  and  several  shades  lighter  underneath.     Those  of  the  old  trees 


"i"1  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION, 


Fig.    8. — FJucalyptus  botryoides.     Natural  size. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  301 

are  long,  slightly  curved  and  sharply  pointed,  somewhat  leathery  in 
texture,  dark  green  on  the  upper  side  and  lighter  in  color  beneath. 

The  buds  are  borne  laterally  and  bloom  during  August  and  Sep- 
tember; umbels  alternate,  solitary,  pedicles  short,  the  buds  with  their 
deciduous  calyx  cups  are  dumb-bell  shaped,  while  the  mature  fruit  is 
egg-shaped,  with  the  valves  three  or  four  in  number,  generally  three, 
enclosed.  The  seed  ripens  during  the  summer  months  and  is  brown  in 
color  and  the  size  of  the  blue  gum  seed,  but  not  so  angular. 

The  lumber  of  the  sugar  gum  is  of  a  yellowish  white  color,  easy  to 
work  when  green  but  very  hard  if  allowed  to  dry.  This  wood  is  very 
closed  grained  and  hard,  and  tested  very  high  at  Berkeley  in  the  tests 
carried  on  by  the  United  States  Forestry  Service.  The  wood  can  be 
used  for  the  same  purpose  as  the  blue  gum  wood,  and  is  durable  under- 
ground. 

Trees  of  this  species  reach  their  best  development  in  the  southern  part 
of  the  State.  The  sugar  gum  has  been  given  a  thorough  trial  in  both 
the  San  Joaquin  and  Sacramento  valleys,  but  in  every  case  known  to  the 
writer  they  have  been  killed  by  the  frost.  Some  of  the  best  growths  of 
this  tree  can  be  seen  at  Riverside,  or  in  the  towns  along  the  coast  from 
San  Diego  to  Santa  Monica.  This  is  one  of  the  trees  much  used  in 
southern  California  as  a  street  tree,  especially  at  and  around  San  Diego. 
It  is  to  be  found  growing  as  wind-breaks  around  Riverside,  San  Bernar- 
dino, Colton,  Ontario,  Pomona,  and  San  Dimas. 

This  species  is  one  of  the  most  drought  resistant  and  valuable  euca- 
lypts  that  can  be  set  out  commercially,  but  it  succumbs  to  frost.  It  is 
of  a  much  slower  growth  than  the  other  commercial  eucalypts,  coming 
after  rostrata,  as  a  rule. 

Von  Mueller  says  of  the  cor y no  calyx:  A  timber  tree  attaining  a  height 
of  120  feet,  length  of  bole  to  60  feet,  circumference  at  5  feet  from  the 
ground  reaching  17  feet.  The  base  of  the  trunk  often  swells  out  in 
regular  tiers.  The  wood  remarkably  heavy,  very  dense,  hard  and  strong, 
less  liable  to  warp  than  that  of  many  other  kinds  of  Eucalyptus  wood 
(J.  E.  Brown).  It  has  come  into  use  for  fence  posts  and  railway 
sleepers,  naves  and  felloes.  Its  durability  is  attested  by  the  fact  that 
posts  set  in  the  ground  fifteen  years,  show  no  sign  of  decay.  The  tree 
thrives  well  even  on  dry  ironstone  ranges.  The  sweetish  and  pleasantly 
odorous  foliage  attracts  cattle,  sheep  and  camels,  which  browse  on  the 
lower  branches,  as  well  as  on  saplings  and  seedlings.  Scarcely  any 
other  eucalypt  is  similarly  eaten  (J.  E.  Brown).  It  should,  therefore, 
be  planted  on  cattle-  and  sheep-runs  in  arid  districts,  to  furnish  addi- 
tional provender. 


302  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 


Fig.  9. — Eucalyptus  corynocalyx.     Natural  size. 


Bulletin  223]       tolerance  of  eucalyptus  for  alkali.  303 

Eucalyptus  Cornuta.     The  Yate. 

Eucalyptus  cornuta,  the  "yate,'.'  is  a  very  attractive,  graceful  tree. 
Its  foliage  is  greener  than  that  of  the  blue  gum,  and  tends  to  persist  in 
the  round  or  oblong  form  of  leaf.  It  is  a  rapid  grower  and  resists 
drought  on  light  soil  better  than  E.  globulus  or  E.  viminalis.  Euca- 
lyptus cornuta  is  one  of  our  hardiest  and  fastest  growing  Eucalypti. 
The  bark  is  a  pleasant  light  drab  color  and  nearly  smooth.  The  tree 
grows  tall,  has  great  vigor  in  our  valleys,  and  the  timber  is  valuable. 
While  it  does  branch  low  it  makes  a  large,  handsome  tree  with  plenty  of 
foliage.  The  flowers  are  so  large  and  close  in  the  umbel  that  each  umbel 
looks  like  a  large,  single,  pompon  flower  of  delicate  light  green  or  light 
straw  color.  Its  name  comes  from  the  long,  horn-like  cap  of  the  flower. 
(Abbot  Kinney.) 

Yon  Mueller  says :  The  yate  tree  of  southwestern  Australia  is  a  large 
tree  of  rapid  growth,  preferring  a  somewhat  humid  soil.  The  wood  is 
used  for  various  artisans'  work,  and  preferred  there  for  the  strongest 
shafts  and  frames  of  carts  and  other  work  requiring  hardness,  toughness 
and  elasticity,  and  is  considered  equal  to  ordinary  ash  wood.  The  tree 
appears  to  be  well  adapted  for  tropical  countries. 

Eucalyptus  Crebra. 
The  narrow-leaved  ironbark-tree  of  New  South  Wales  and  Queensland. 
Wood  reddish,  hard,  heavy,  elastic  and  durable ;  much  used  in  the  con- 
struction of  bridges  and  for  railway  sleepers,  also,  for  wagons,  piles, 
fence  posts.  This  species  is  of  an  erect  growth  and  has  a  very  rough, 
persistent  bark  of  a  light  grayish  color,  the  rough  bark  extending  to  the 
limbs  and  small  twigs,  which  are  smooth.  The  leaves  are  long,  narrow, 
equally  dark  green  on  both  sides  and  pendulous,  giving  the  trees  a  weep- 
ing effect.  The  mature  seed  cases  are  borne  in  paniculated  umbels,  and 
are  small  cup-shaped,  with  the  valves,  generally  four  in  number,  en- 
closed. The  wood  is  hard,  durable  and  of  a  reddish  color,  considered 
valuable.  This  species  has  the  power  to  resist  frosts  and  is  found  grow- 
ing in  Fresno  and  in  the  southern  part  of  the  State.  It  is  being  set  out 
in  great  numbers  at  the  present  time  by  companies,  in  commercial  plant- 
ings. In  rapidity  of  growth  this  species  ranks  near  the  Eucalyptus 
rostrata. 

Eucalyptus  Globulus.  Blue  Gum. 
Individuals  of  this  species  grow  erect  as  a  rule,  branching  low  in 
isolated  specimens,  while  those  in  close  plantings  have  small  crowns  and 
are  practically  free  from  lateral  branches.  The  bark  of  the  seedlings 
is  light  bluish  green  in  color,  while  that  of  the  trunks  of  the  old  trees 
varies  from  a  light  brown  to  a  gray  or  greenish  color  due  to  the  flaking 
off  of  the  bark  in  long  strips.     The  limbs  are  generally  smooth. 


30-i  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 


Fig.   10. — Eucalyptus  crebra.     Natural  size. 


BULLETIN  225]        TOLERANCE   OF   EUCALYPTUS   FOR   ALKALI.  305 

The  stems  of  the  seedlings  are  rectangular  in  shape,  while  their  leaves 
and  those  of  the  sprouts  of  the  old  trees  are  opposite,  oblong,  blmitv 
pointed,  and  of  a  light  bluish  green  color,  darker  on  the  upper  side  of 
the  leaf.  Those  of  the  old  trees  are  elongated,  sickle-shaped,  leathery 
in  texture,  and  equally  dark  green  on  both  sides. 

This  species  is  in  bloom  from  January  to  May,  the  flowers  beinir 
white  in  color,  generally  solitary,  axillary  and  borne  on  short  stalks. 
The  whitish  buds  are  angular,  with  a  bluntly-pointed  saucer-shaped 
deciduous  cap,  while  the  mature  fruit  is  dark  green  in  color,  with  from 
three  to  five  valves,  generally  four,  barely  enclosed. 

Trees  of  this  species  endure  the  frosts  of  the  Sacramento  Valley  as  far 
north  as  Red  Bluff,  Tehama  County,  and  the  dry  heat  of  the  San  Joaquin 
Valley.  It  is  found  in  nearly  every  town  south  of  San  Francisco  to 
San  Diego,  and  out  of  the  edge  of  the  Imperial  desert  region.  A  large 
number  of  blue  gum  seedlings  have  been  set  out  in  Imperial  Valley,  but 
nearly  all  have  died  on  account  of  the  intense  heat,  while  the  trees  of  the 
species  rostrata  and  rudis  have  survived  the  heat  and  are  making 
wonderful  growths  under  irrigation. 

The  blue  gum  reaches  its  greatest  development  along  the  coast  and 
river  bottoms,  where  the  annual  rainfall  is  fifteen  or  more  inches,  and 
foggy  days  are  common;  although  trees  of  this  species  are  to  be  found 
growing  on  lands  varying  from  an  alkali  to  a  rich  loam,  and  at  varying 
elevations  from  river  bottoms  to  hilltops. 

The  lumber  of  this  species  is  durable  above  ground,  and  is  being- 
sawed  at  San  Jose,  California,  for  the  felloes,  poles,  reaches  and  single- 
trees of  wagons,  and  flooring,  insulator  pins,  and,  in  fact,  anything  that 
requires  strength.  It  is  valued  at  the  same  price  as  that  of  oak  lumber, 
which  it  is  slowly  replacing.  The  wood  is  yellowish  white  in  color, 
closed  grained  and  easily  polished.  It  has  a  tendency  to  chip  when 
planed,  on  account  of  a  wavy  grain. 

The  leaves  from  the  blue  gum  furnish  practically  all  of  the  Euca- 
lyptus oil  in  this  country,  as  it  is  claimed  by  the  distillers  that  it  is  the 
only  species  producing  sufficient  quantity  of  oil  per  hundred  pounds 
of  leaves  to  make  distilling  a  profitable  business. 

This  species,  Eucalyptus  globulus,  is  undoubtedly  better  known  than 
any  of  the  other  eucalypts  in  this  State,  and  is  recognized  generally  in 
the  State  as  one  of  the  fastest  growing  trees  in  the  world. 

Mr.  Abbot  Kinney  says  of  the  globulus:  The  blue  gum  is  a  sort  of 
average  Eucalyptus,  tall,  but  not  the  tallest ;  used  for  general  purposes, 
even  to  piling  and  ship  building;  it  is  not  the  best  of  timber  for  any 
of  these  purposes;  not  the  most  lasting  in  the  air,  ground  or  water; 
not  the  highest  yield  of  oil;  not  the  best  honey-making  tree  for  bees. 
It  is  still  well  up  in  all  of  these  respects.  Like  nearly  all  eucalypti  the 
tree  should  be  cut  when  the  sap  is  least  active  and  should  be  worked 


306  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION. 


Fig.  11. — Eucalyptus  globulus.     Natural  size. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  307 

into  its  final  form  of  firewood,  boards,  etc.,  as  soon  as  possible  after  it 
is  felled.  I  have  seen  blue  gum  logs  become  so  hard  that  the  cost,  from 
increased  difficulty  of  handling,  ate  up  more  than  the  final  value.  In 
many  places  this  tree  does  well  singly  and  in  single  lines,  and  it  will 
furnish  a  continuous  supply  of  firewood,  as  on  the  borders  of  fields  and 
orchards  that  are  cultivated,  when  it  will  amount  to  little  or  nothing 
in  solid  plantations.  *  *  *  A  continuous  supply  of  firewood  can 
be  obtained  from  the  blue  gum  by  pollarding  or  cutting  the  tree  back 
every  three  or  four  years;  it  stands  this  treatment  especially  well  while 
some  of  the  other  species  do  not  take  kindly  to  it.  The  sprouting  of 
the  blue  gum  when  cut  adds  to  its  value  as  a  fuel  tree,  for  in  all  planta- 
tions it  makes  its  first  crop  in  about  seven  years  and  than  for  an  indefi- 
nite period  renews  the  crop  every  three  or  five  years. 

The  E.  globulus  accommodates  itself  to  more  conditions  in  a  satis- 
factory way  than  any  other  Eucalyptus.  Yet  there  is  no  one  condition 
for  which  some  other  species  of  this  genus  is  not  better  adapted.  So 
also  there  is  no  use  to  which  the  blue  gum  is  put  for  which  another 
species  is  not  more  serviceable. 

Eucalyptus  Gunnii.     Swamp  Gum  Tree. 

In  the  lowland  along  fertile  valleys  E.  Gunnii  attains  a  considerable 
size  and  supplies  a  strong,  useful  timber.  It  is  this  species  that  survived 
the  severe  frosts  at  Kew  Gardens.  Bees  obtain  unusually  much  honey 
from  the  flowers  of  this  species.  Cattle  and  sheep  browse  on  the  foliage. 
(Von  Mueller.) 

Mr.  Abbot  Kinney  describes  it  as  being  a  green,  attractive  looking 
and  rapid  growing  tree  and  often  a  very  fantastic  grower  in  California, 
bending  entirely  over  and  sweeping  the  ground  with  its  branches;  it  is 
one  of  the  best  frost  resisters  among  the  eucalypts  but  contains  only  a 
small  per  cent  of  oil. 

Eucalyptus  Robusta.     Swamp  Mahogany. 

The  swamp  mahogany  is  one  of  the  erect,  but  slow  growing  eucalypts. 
The  trunks  of  the  young  trees  are  of  a  reddish  gray  color,  slightly 
rough  or  stringy,  while  the  limbs  are  smooth  and  dull  red.  The  bark 
of  the  old  trees  is  very  rough,  stringy  and  persistent. 

The  leaves  are  of  a  leathery  texture,  broad  and  lance-shaped,  with  the 
veins  parallel  and  nearly  at  right  angles  to  the  midrib;  in  color  they 
are  dark  green  on  the  upper  surface,  while  the  under  surface  is  several 
shades  lighter. 

The  buds,  with  their  deciduous  calyx  caps,  are  club-shaped  and  are 
borne  in  clusters  of  five  to  eleven.    These  clusters,  or  umbels,  are  axillary 
and  their  stalks  are  flattened.     The  mature  seed  cases  are  deep  cup- 
shaped,  with  the  valves  enclosed. 
5 — bul  225 


308  UNIVERSITY  OF   CALIFORNIA EXPERIMENT   STATION. 


Fig.   12. — Eucalyptus  robusta.     Natural  size. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  309 

The  wood  is  not  very  valuable  to  work,  as  it  is  very  brittle,  but  it  is 
durable  in  the  soil.  The  trees,  if  grown  in  a  place  exposed  to  the  wind, 
are  liable  to  break  off  when  they  have  reached  a  height  of  from  15  to 
30  feet. 

Eucalyptus  robust  a  is  much  used  for  street  planting,  and  makes  one 
of  the  best  street  trees  to  be  found  among  the  species  of  Eucalyptus, 
except  for  its  tendency  to  break  down.  It  will  withstand  low  temper- 
atures. 

It  reaches  its  greatest  development  where  there  is  plenty  of  Avater, 
as  in  river  bottoms,  swamps  and  depressions  in  fields  where  the  winter 
rains  settle. 

Eucalyptus  Rostrata.     Red  Gum. 

Trees  of  this  species  are  of  a  slower  growth  than  the  blue  gum  and 
grow  ver}^  crookedly  even  in  close  plantings. 

The  bark  of  the  seedlings  and  the  twigs  of  the  old  trees  have  a  reddish 
hue,  while  that  of  the  trunks  of  the  mature  trees  is  a  very  dark  gray, 
varying  from  smooth  and  non-persistent  in  some  trees  to  others  where 
it  is  deeply  furrowed  and  persistent.  The  limbs  are  much  lighter  than 
the  trunk  and  smoother. 

The  leaves  of  the  seedlings  are  broad  lance-shaped,  darker  in  color  on 
the  upper  side,  while  those  of  the  older  trees  are  elongated,  narrow, 
sickle-shaped,  and  equally  green  on  both  sides.  The  umbels  are  solitary 
and  axillary.  The  flowers  are  borne  in  clusters  of  from  three  to  four- 
teen, generally  seven,  in  one  fourth  inch  pedicels. 

The  buds,  with  their  hemispherical,  sharply-pointed  lids,  are  nearly 
round  and  a  little  larger  than  a  BB  shot,  valves  three  to  five  in  number, 
generally  four,  very  much  protruding  on  the  mature  fruits. 

The  wood  of  the  red  gum  is  very  durable  both  above  and  below 
ground  and  can  be  easily  wTorked  when  green.  It  is  possible  to  saw  the 
wood  up  into  the  thinnest  of  lumber  and  veneers.  In  color  the  wood 
varies  from  a  very  light  to  a  dark  blood  red.  This  is  very  heavy  and 
takes  a  fine  polish,  but  according  to  strength  tests  it  is  inferior  to  both 
sugar  and  blue  gums. 

The  present  range  of  Eucalyptus  rostrata  extends  south  from  Chico, 
Butte  County,  in  the  Sacramento  Valley,  throughout  the  San  Joaquin 
Valley,  into  the  southern  part  of  the  State,  and  this  species  has  shown 
its  ability  to  stand  the  intense  heat  of  the  Imperial  Valley  throughout 
its  entire  length  to  Calexico  on  the  Mexican  border.  In  every  instance 
where  this  tree  was  found  in  the  Imperial  Valley  it  was  making  a  good 
growth,  with  proper  care,  notwithstanding  the  heat. 

The  red  gum  makes  a  good  growth  on  alkali  soils  in  the  San  Joaquin 
Valley  and  is  one  of  our  most  drought  resistant  trees  of  any  commercial 


310  UNIVERSITY   OF    CALIFORNIA EXPERIMENT    STATION 


Fig.   13. — Eucalyptus  rostrata.     Natural  size. 


Bulletin  225]      tolerance  of  eucalyptus  for  alkali.  311 

value,  other  than  the  sugar  gum  or  corynocalyx.     It  is  a  slow  growing 
species  in  regard  to  height,  but  one  of  the  first  in  regard  to  diameter. 

Baron  von  Mueller  thus  speaks  of  the  rostrata:  It  attains  excep- 
tionally a  height  of  200  feet  with  a  comparatively  slight  stem,  but  it  is 
mostly  of  a  more  spreading  habit  of  growth  than  the  majority  of  its  tall 
congeners.  The  timber  is  one  of  the  most  highly  esteemed  in  all  Aus- 
tralia among  that  of  the  eucalypts,  being  heavy,  hard,  strong  arid 
extremely  durable,  either  above  or  under  ground  or  in  water.  For  these 
reasons  it  is  very  much  prized  for  fence  posts,  piles  and  railway  sleepers. 
For  the  latter  purpose  it  will  last  at  least  a  dozen  years,  but  if  well 
selected  much  longer.  Indeed,  sleepers  were  found  quite  sound  after 
being  24  years  in  use.  It  is  also  extensively  employed  by  ship  builders 
for  main  stem,  stern  post,  inner  post,  deadwood,  floor  timbers,  transoms, 
knighthead,  hawse  pieces,  bottom  planks,  breast  hooks  and  riders,  wind- 
lass and  bow  rails.  It  should  be  steamed  before  it  is  worked  for  plank- 
ing. Also  largely  used  for  felloes,  buffers,  and  posts  and  any  parts  of 
structures,  which  come  in  contact  with  the  ground;  not  surpassed  in 
endurance  for  woodbricks  in  street  paving  and  for  tramways. 

Eucalyptus  Rudis. 

Trees  of  this  species  are  erect,  branching  low  in  individual  specimens, 
but  having  clean  trunks  in  close  plantings.  The  bark  of  the  trunks  is 
persistent,  slightly  rough,  but  not  deeply  furrowed;  in  color  it  is  gray. 
The  leaves  of  the  young  plants  are  oval  and  of  a  purple  hue,  while  those 
of  the  old  trees  vary,  oval  to  lance-shaped.  The  buds,  with  their  blunt, 
cone  shaped  deciduous  calyx  caps,  are  borne  on  medium  length  stalk- 
lets,  in  clusters  of  from  five  to  nine.  The  solitary  umbels  are  axillary. 
The  mature  seed  cases  are  broad  cup-shaped,  with  the  valves,  from  four 
to  six  in  number,  slightly  protruding. 

There  are  two  different  trees  in  the  State  recognized  as  Eucalyptus 
rudis:  the  tree  called  rudis  local  in  the  southern  part  of  the  State 
has  a  smooth-barked  trunk,  as  a  rule,  and  the  wood  is  inferior,  dark 
brown  in  color  and  light. 

The  species  described  grows  in  the  vicinity  of  Fresno,  and  is  a  supe- 
rior tree,  with  the  wood  of  a  light  brown  color,  hard  and  easily  polished. 

The  wood  of  this  latter  tree  is  very  durable ;  there  are  records  of 
posts  standing  in  the  ground  for  eleven  years  without  signs  of  decay. 

Eucalyptus  rudis  is  capable  of  enduring  low  temperatures,  as  well  as 
the  globulus. 

The  rudis  in  Arizona  called  the  desert  gum,  is  reported  by  the  experi- 
ment station  (Timely  Hints  for  Farmers,  No.  68)  as  being  one  of  the 
most  rapid  growing  of  the  eucalypts,  especially  when  young.  At 
"Tucson  it  has  shown  itself  extremely  resistant  to  summer  heat  and 
winter  cold,  having  never  suffered  therefrom;  it  is  also  drought  re- 
sistant." 


312 


UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION. 


Fig.   14. — Eucalyptus  rudis.     Natural  size. 


Bulletin  225]       tolerance  of  eucalyptus  for  alkali.  313 

Eucalyptus  Sideroxylon  var.  Rosea.     Victoria  Ironbark. 

This  species  has  a  tendency  to  grow  crooked  and  branched.  The 
black  bark  is  deeply  furrowed  and  persistent,  giving  to  the  trees  a 
burned  appearance,  which  is  characteristic  of  this  variety.  The  foliage 
of  the  tree  is  beautiful,  of  a  bluish  tint  and  pendulous,  producing  a 
weeping  effect.  The  leaves  are  of  medium  width  and  length,  of  a  light 
bluish  green  color.  The  buds  are  borne  in  solitary  axillary  umbels,  in 
clusters  of  generally  seven  on  one  fourth  inch  stalklets.  In  shape  they 
are  cylindrical,  with  a  conical  calyx  cap.  The  flowers  are  pinkish  in 
color  and  in  bloom  from  March  to  June. 

The  mature  seed  cases  are  deep  cup-shaped  with  the  rim  compressed, 
and  the  valves,  which  vary  from  four  to  six,  deeply  enclosed.  The 
wood  of  this  species  is  of  a  dark  brown  color  and  particularly  hard, 
heavy  and  durable. 

Eucalyptus   Tereticornis.     Forest   Gray   Gum. 

This  species  is  of  a  very  erect  habit  of  growth,  both  in  close  plantings 
and  isolated  specimens.  The  branches  are  few  and  scattering,  leaving 
the  crown  open.  The  deciduous  bark  of  the  trunks  of  the  old  trees  is 
generally  smooth  and  of  a  mottled  color,  from  light  brown  to  cream, 
directly  after  the  bark  has  been  shed.  The  buds  are  in  bloom  during 
May  and  June,  and  are  borne  laterally  in  solitary  umbels,  in  clusters 
of  from  five  to  nine,  on  short  stalklets.  The  deciduous  lid  is  horn- 
shaped;  reddish  brown  in  color,  just  before  blooming  time. 

The  seed  cases  are  slightly  larger  than  those  of  Eucalyptus  rostrata; 
with  the  valves,  three  to  five  in  number?  generally  four,  protruding  and 
hemispherical.  The  leaves  of  the  young  plants  are  broad  lance-shaped, 
while  those  of  the  old  trees  are  long,  of  medium  width  and  light  green 
on  both  sides.  The  pendulous  branches  with  their  long  leaves  give  to 
the  trees  a  weeping  effect.  The  wood  of  this  species  is  close  grained 
and  durable,  varying  in  color  from  a  white  to  a  light  brownish  red,  and 
can  be  used  in  wheelwright's  work,  etc. 

Undoubtedly  Eucalyptus  tereticornis  can  withstand  as  wide  a  range 
of  temperature  and  of  variation  in  soils,  over  as  large  a  range  of  the 
State,  as  the  red  gum. 


314  UNIVERSITY   OF   CALIFORNIA — EXPERIMENT   STATION. 


Fig.   15. — Eucalyptus  sideroxylon.     Natural  size. 


Bulletin  225]       tolerance  of  eucalyptus  FOR  ALKALI.  315 


Fig.    16. — Eucalyptus   tereticornis.      Natural   size. 


316  UNIVERSITY  OF   CALIFORNIA — EXPERIMENT   STATION. 

Eucalyptus  Viminalis.     Manna  Gum. 

There  are  two  varieties  of  this  species,  both  erect-growing  trees.  The 
trunks  of  one  variety  have  a  bark  not  dissimilar  to  that  of  the  globulus 
while  that  of  the  other  has  a  smooth  bark,  white  in  color  and  deciduous. 
The  bark  is  shed  each  year  just  as  the  trees  are  entering  the  blooming 
period.  The  leaves  of  the  young  plants  and  the  sprouts  of  the  old  trees 
are  from  two  to  three  inches  long,  narrow  and  opposite ;  while  those  of 
the  old  trees  are  long,  narrow,  slightly  curved,  of  a  dull  green  color, 
pointed  and  pendulous,  giving  to  the  trees  a  weeping  effect.  The  stem- 
less  buds,  with  their  conical,  deciduous  calyx  cap,  are  borne  in  threes 
on  slightly  flattened  stalks.  The  mature  seed  cases  are  goblet-shaped, 
with  the  valves,  four  in  number,  barely  protruding. 

The  wood  of  the  species  is  inferior  to  that  of  the  red  gum,  both  in 
strength  and  durability,  although  it  is  useful  in  rough  carpentry,  and 
in  making  fruit  boxes,  or  any  other  light  shipping  boxes.  In  color  the 
sap  wood  is  light  brown,  changing  to  a  yellowish  white  in  the  older  wood. 

The  viminalis  or  manna  gum  withstands  low  temperatures  equally 
as  well  as  the  red  gum  or  the  blue  gum,  and  is  growing  at  Chico,  Butte 
County,  in  greater  numbers  than  any  other  eucalypts. 

Although  this  species  is  not  a  very  valuable  timber  tree,  it  makes  an 
average  wood  for  fuel  purposes,  and  can  be  grown  on  land  under  condi- 
tions where  many  of  the  other  and  more  valuable  species  would  barely 
live  and  make  only  an  inferior  growth. 

Von  Mueller  in  describing  this  species  remarks  that  in  the  rich  soil 
of  the  mountain  forests  of  Australia  it  attains  gigantic  dimensions, 
rising  to  a  height  of  rather  more  than  300  feet,  with  a  stem  occasionally 
15  feet  in  diameter.  It  is  the  only  species  of  eucalypt  which  yields  the 
crumb-like  melitose-manna  copiously. 


BXJIXETIN-225]         TOLERANCE    OP    EUCALYPTUS    FOR    ALKALI. 


31' 


